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2 A VIATION EQUIPMENT
Upon completion of this chapter, you should be able to do the following:
• Describe the Ship’s Aviation Equipment systems and its associated components. • Identify the purpose and principles of operation of the components of Aviation Equipment systems. • Describe the procedures to follow when troubleshooting the Aviation Equipment systems • Describe the procedures to follow when performing maintenance on the Aviation Equipment systems
2.0.0 INTRODUCTION In this chapter you will be introduced to various pieces of Aviation Equipment, their uses, how they function, and your responsibilities as a maintainer for the systems and components. 2-1 UNCLASSIFIED
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2.1.0 STABILIZED GLIDE SLOPE INDICATOR (SGSI) SYSTEM The stabilized glide slope indicator (SGSI) system consists of a GSI cell mounted on top of an electrohydraulic stabilized platform. The GSI cell is an optical viewing system used to indicate to a pilot the aircraft approach angle to a landing platform or ship. The GSI system is an electrohydraulic optical landing aid designed for use on ships equipped for helicopter operations. By use of the SGSI, a helicopter pilot may visually establish and maintain the proper glide slope for a safe landing. The system is self-contained, relying on the ship for 115 volts ac 400-Hz and 440 volts ac 60-Hz power.
The GSI, which is mounted on a stable platform, provides a single bar of light either green, amber, or red (fig. 2-1). The cell face acts as a window through which the pilot views the light. The color of the light bar indicates to the pilot of the approaching aircraft whether the aircraft is above (green), below (red), or on (amber) the correct glide slope. By varying the aircraft altitude to keep the amber light bar visible, the pilot maintains the correct glide path to the ship’s landing pad. The bar of light is formed by the combined actions of source light, Fresnel lens, and lenticular lens.
Figure 2-1.-Glide slope indicator and light beam.
To steady the GSI with respect to the pitching and rolling motions of the ship, the light cell is mounted on an electrohydraulic stabilized platform. This equipment uses a local gyro for reference and develops electronic error signals that, in turn, control hydraulic cylinders that move the platform in the opposite direction to the ship’s pitch and roll axis. The system incorporates a failure detection circuit that turns off the lights in the event of stabilization failure. 2-2 UNCLASSIFIED
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2.1.1 SGSI System Components The assemblies that comprise the SGSI system are as follows (fig. 2-2): • Electronic enclosure assembly • Remote control panel assembly • Hydraulic pump assembly • Transformer assembly • GSI assembly • Stabilized platform assembly 2-3 UNCLASSIFIED
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Figure 2-2.-Stabalized Glide Slope Indicator (SGSI) System. 2-4 UNCLASSIFIED
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Electronics Enclosure Assembly The electronics enclosure assembly (fig. 2-3) is the signal processing distribution and control center for the system. It contains the circuits, amplifiers, and other electrical and electronic components required to control the major components of the system.
Figure 2-3.-Electronics Enclosure Assembly (F100).
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To understand the system operation, you must understand feedback control systems. A feedback control system compares an input signal with a reference signal and then generates an error signal. This error signal is then amplified and used to drive the output in a direction to reduce the error. This type of feedback system is often referred to as a servo loop. A gyro, mounted on the stabilized platform, acts as the reference of the system. Since the gyro is stable, synchro transmitters located on the gimbals will sense any motion of pitch or roll. As the ship begins to pitch or roll, an error signal is developed by the synchro transmitter stators. Look at the block diagram in figure 2-4 and follow the path of the error signal through the electronic enclosure assembly. (The block diagram represents either the pitch or the roll control loops. They are identical electrically.)
Figure 2-4.-Stabalization circuits block diagram.
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From the transmitter stators the error signal is sent to the gyro demodulator, where the signal is changed from ac to dc. The signal then goes through a stab-lock relay (described later) and is amplified as it moves through the servo amplifier, which in turn operates the servo valve. The servo valve opens and allows hydraulic fluid to enter the hydraulic actuator (fig, 2-5), thereby leveling the platform and thus canceling the error signal.
Figure 2-5.-Stabilized platform assembly functional diagram. When this occurs, a READY light is actuated on the remote control panel. If the system develops a malfunction and the error signal is not canceled, an error sensing circuit will light the NOT READY light on the remote control panel and turn off the GSI.
In the previous paragraphs, we discussed the normal mode of operation in the electronics portion of the system. The stabilization lock feature (stab-lock relay) tests and aligns the GSI. Referring to figure 2-6, you will see internal gyro stab-lock and ship gyro stab-lock push buttons and two test switches, one of which is pitch-off-roll.
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Figure 2-6.-Components panel assembly (P/O electronics enclosure-F100) controls and indicators.
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As previously mentioned, the error signal in the normal mode goes through a stab-lock relay. When the stab-lock button is pushed, the normal error signal supplied from the gyro is stopped at this point (see fig. 2-7). When the stab-lock button is pushed, the error signal comes from the linear voltage differential trans-former (LVDT) when the test switch is in the off position. The core of the LVDT is mechanically attached to the hydraulic actuator, which levels the platform. As the actuator moves, the core also moves, thereby supplying a signal proportional to the amount of roll or pitch. These signals can be measured to aid in the maintenance and alignment of the system. Revisions are also made to drive the platform manually using the test switches and the manual drive potentiometer.
Figure 2-7.-Stabilization control circuit-signal flow.
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Remote Control Panel Assembly The remote control panel (fig. 2-8) is located in the flight operations control room. The panel provides control and indicators for operating and monitoring the SGSI system from a remote location. It contains the READY and NOT READY lights described previously. The panel also contains an OVERTEMP light to indicate when the hydraulic fluid is heated to a temperature higher than 135°F±5°, a source failure light to indicate that one or more of the GSI source lights are burned out, a variable transformer to control the intensity of GSI light, and a panel illumination control. A standby light will be energized when the main switch on the electronic enclosure assembly is on.
Figure 2-8.-Remote Control Panel Assembly (F200).
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Hydraulic Pump Assembly The hydraulic pump assembly (fig. 2-9) is a self contained medium-pressure, closed-loop system used to supply hydraulic pressure for the stabilized platform. This assembly consists of an electric pump motor, a coupling unit, a hydraulic pump reservoir, valves, piping, and an electrical system. All components are mounted on a steel base with isolation mounts and comprise a complete self contained 1400-psi hydraulic power supply.
Figure 2-9.-Hydraulic Pump Assembly (F300). 2-11 UNCLASSIFIED
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Hydraulic fluid is stored in a reservoir and piped to a motor-driven pump. The output is pressurized by the pump to 1400 psi, filtered, and piped to the power supply output line where it is available to the external system through a shutoff valve. On the return line, fluid is returned from the external system to the reservoir at a reduced pressure of 75 psi. A shutoff valve is also used in this low-pressure line. Electrical power is obtained from ship’s power system and connected through the motor controller and junction box. This assembly is located as close as possible to the stabilized platform. It provides hydraulic fluid at 1400 psi to the hydraulic actuator on the stabilized platform. The motor and controller operate on 440-volt, 3-phase received from normal ship’s power supply. The temperature switches (not shown) operate the OVERTEMP light on the remote control panel. Also, a pressure switch in the hydraulic pump discharge line will close at 1200 psi. If not closed, the pressure switch will de-energize the electronic panel assembly on low oil pressure. Hydraulic fluid heaters in the oil reservoir maintain the temperature at approximately 70°F±5°.
Transformer Assembly
The transformer assembly is a weather tight enclosure mounted within 3 feet of the stabilized platform. An interconnecting cable, which is part of the transformer assembly, connects the transformer assembly to the GSI. This assembly is located as close as possible to the stabilized platform. Its purpose is to step down the voltage for the source light (GSI) from 115 volts ac to 18.5 volts ac.
Glide Slope Indicator Assembly
The GSI assembly consists of two major subassemblies: the mounting base assembly and the indicator assembly. The indicator assembly is supported in the mounting base assembly, which is mounted on the stabilized platform. The incoming system cable connects at the rear of the right-hand heater compartment. The mounting base assembly provides the means to accurately position the indicator assembly in relation to the landing pad. The mounting base is then secured in this position by the retractable plunger. Indicator elevation is controlled by the elevation adjustment knob. The GSI sits in the trunnions of the mounting base assembly.
Stabilized Platform Assembly
The stabilized platform assembly is mounted to the ship’s deck in close proximity to the helicopter landing area. This assembly contains a local gyro, gimbaled platform, hydraulic cylinders, and electrically operated servo valves. More information on the stabilized platform is given later in this chapter.
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GSI Cell Assembly The Glide Slope Indicator (GSI) cell is an optical viewing system used to indicate to a pilot his aircraft approach angle to a landing platform or a ship.
The indication that the pilot sees is a three color display of which only one color (or a mixing at the interface) is seen.
The cell face acts as a window through which the pilot views the light. The light will be colored depending on which portion of the window the pilot is looking through (see Figure 2-10).
Figure 2-10.-Simplified Cell Schematic.
Figure 2-10 is a simplified schematic of the cell. The actual cell uses a ground glass diffuser which evens the light bar intensity. A Fresnel lens (which permits the use of a shorter cell length) and a lenticular lens to color and spread the light horizontally.
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Figure 2-11 is a simplified functional diagram of the GSI as it appears in the system. The action of this cell is exactly the same as that described in Figure 2-10.
Figure 2-11.-Glide Slope Indicator, Simplified Functional Diagram.
The cell is usually set on a three degree glide slope as its red/amber intersection and it has a horizontal coverage of forty degrees (see Figure 2-12).
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Figure 2-12.-Viewing zone of glide slope indicator.
2.1.2 Principles of Lenses used in the GSI System There are two types of lenses used in the optical portion of the Glide Slope Indicator system: The Fresnel lens and the lenticular lens. A discussion of the principles of the plano-convex lens is provided so that the physical characteristics of this type of lens may be compared with the physical characteristics of the Fresnel lens.
PLANO-CONVEX LENS
A plano-convex lens has a plane, or flat surface and a spherical surface. A plano-convex lens is a positive or collective lens, that is, a lens in which the light rays are collected together at a focus point and thus form. an image. The radius of the spherical surface of the lens is known as the radius of curvature.
FRESNEL LENS The Fresnel lens in this system is a lightweight and relatively thin sheet of transparent lucite. The refraction of light rays by the Fresnel lens is collective, as in a plano-convex lens; however. The Fresnel lens differs in configuration from a plano-convex lens, as shown in Figure 2-13. One surface of the Fresnel lens consists of a number of stepped facets. These facets are circular, concentric grooves that extend from the center of the lens to the edges.
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Figure 2-13.-Comparison of Physical Characteristics of Plano-Convex Lens and Fresnel Lens.
The slope of each facet is independent of the slope of all other facets. These slopes are designed to provide a perfect focus of the light rays which pass through the lens. This provides an advantage over a plano-convex spherical lens, which causes spherical aberration of light rays, as illustrated in Figure 2-14. When the rays of light, parallel to the principal axis of a convex spherical lens, pass through zones near the edge, the principal focus occurs at a point which is closer to the lens than the focus for rays which pass through the lens near the principal axis. Therefore, the light rays from a plano- convex spherical lens tend to scatter. The Fresnel lens can also be formed around a suitable radius to minimize astigmatism. Astigmatism of a lens is the inability of the lens to bring all of the light rays from a point on an object to a sharp focus to form the image.
Figure 2-14.-Comparison of Optical Characteristics of Plano-Convex Lens and Fresnel Lens. 2-16 UNCLASSIFIED
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The optical characteristics of the Fresnel lens will vary with a change in temperature. If the lens temperature is allowed to vary, three effects will be observed. First, if the temperature varies, the size of the bar of light near the center of the lens is different from that which is seen near the center of the lens when the lens is at design temperature. Also, as the observer moves up or down, the size of the bar of light appears to change as the image moves from the lens center.
The second effect that will be observed is that the bar will have a more noticeable bend when the lens is not at design temperature.
The last effect that will be observed is that the vertical field angle is larger when the ambient temperature is higher than design temperature and smaller when the ambient temperature is lower than the design temperature (Figure 2-15). To maintain design characteristics of the Fresnel lens. The lens-heating compartments are maintained at a temperature which is relatively constant. The Fresnel lens is enclosed in a separate compartment in which the lenticular lens serves as the front and an optical glass serves as the back of the compartment. Hot air is circulated in the compartment under thermostatic control.
Figure 2-15.-Vertical Field Angle.
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The GSI cell, unlike its similar cousin the Fresnel Lens Optical Landing System (FLOLS) cell, does not require close temperature control; however the heaters and blowers are necessary to keep condensation from forming on the back of the lenticular lens.
LENTICULAR LENS A lenticular lens is placed in front of the Fresnel lens. The lenticular lens consists of many long, convex, cylindrical lenses placed side by side as shown in Figure 2-16. Each individual lens has the same short focal length. The viewing area of the object is spread by the short focal length of the lenticular lens. If the object consists of a multiple light source with spacing between the lights, the object appears to an observer looking into the lens as a continuous band of light which fills the width of the lens. In the GSI system, the arrangement of the lens with respect to the source lamps and the physical properties of the lens cause the source lamps to appear as a common light image 12 inches wide and approximately 1/2 inch high. The object appears as a continuous hand of light regardless of the observer's position in the azimuthal range of view of the lenticular lens. The azimuthal range is the angular position (expressed in degrees) in a horizontal plane in which a pilot of an approaching aircraft can observe the band of light. The azimuthal range of the lenticular lens used in the GSI system is forty degrees. The appearance of-the object height is not affected by the lenticular lens.
Figure 2-16.-Optical characteristics of Lenticular Lens.
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The lenticular lens in the GSI assembly is manufactured with three different color segments to eliminate the need for filters and their subsequent light attenuation. The top segment is colored green, the middle is amber and the large bottom segment is red. When projected, the resulting glide path has the viewing zone shown in Figure 2-12. The GSI cell was designed so one inch on its face is equal to one degree of arc. Thus the one degree amber is one inch on the cell face.
The stowlock assembly provides a means of securing the source light indicator in a fixed position when the system is not in operation. The stowlock assembly is located directly below the source light indicator assembly and is secured to the deck-edge boom. The shipbuilder’s junction box is used as a junction point for various cables of the system, as are all junction boxes that are a part of the system.
2.1.3 System Operation, Troubleshooting, and Maintenance The following paragraphs provide information on operating, checking-out, troubleshooting, and maintaining the SGSI system. We will discuss some of the things that can be done to keep the SGSI operating efficiently.
When troubleshooting the SGSI system, you should refer to the troubleshooting charts in the Stabilized Glide Slope Indicator (SGSI) Mk 1 Mod 0 (Incorporating Gyro Failure Alarm) for Air Capable and Amphibious Assault Ships, NAVAIR 51-5B-2, technical manual. By using the charts/tables in the technical manual for overall system checkout procedures, you will know what controls must be set during the performance of the checkout procedure. These tables also list the location of each control, the necessary instructions for the proper use of these controls, and the normal indications that should be observed during the operation of these controls. When an abnormal indication is observed during the checkout procedures, certain additional procedures must be performed that use the controls available within the equipment to establish conditions that enable maintenance personnel to isolate malfunctions with a minimum use of test equipment. By using these procedures, you can locate the cause of the specific malfunction and perform the recommended corrective maintenance.
Maintenance is an ongoing process to keep the equipment operating efficiently and consists of preventive and corrective maintenance. For all maintenance requirements for the SGSI system, you should refer to the maintenance requirement cards (MRCs). There are maintenance items to be performed weekly, quarterly, semiannually, and annually. System maintenance must be performed on a regular basis regardless of use cycle. Deterioration and/or damage to equipment may result if system maintenance is not performed regularly. The information given in the following paragraphs is not intended to replace preventive maintenance cards or the applicable technical manuals. This information should familiarize you with some of the requirements and procedures to keep the equipment in top notch operating condition. 2-19 UNCLASSIFIED
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Gyro Alarm Off If a failure occurs in the error sensing circuitry or if the ship’s gyro information or gyro reference voltage is not being sent to the SGSI, a ready light cannot be obtained. This will keep the lamp relay de-energized and not allow the source lamps to illuminate. Operation in the internal gyro mode is still possible through the activation of the gyro alarm off switch-indicator on the component panel assembly. Since the gyro alarm off switch- indicator disables the independent failure detection circuit, a gyro alarm off indicator is automatically illuminated in both the electronic enclosure and the remote control panel. Servo error sensing is not affected by activation of gyro alarm off. Depressing the gyro alarm off push button will activate the ready light and allow the source lamps to illuminate if no other system problems exist.
Gyro Failure Alarm Circuit Tests
These tests are to be performed once a week when the SGSI is being used for air operations. These tests will ensure that all failure monitoring circuits are operational.
Vertical Gyroscope The vertical gyroscope is basically a mechanical device. The essential element of the gyroscope is a flywheel rotating at high angular velocity about an axis. The flywheel is mounted within gimbals that allow it two degrees of freedom as shown in figure 2-17.
Figure 2-17.-Vertical gyro, simplified schematic.
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When the flywheel of the gyroscope is rotating at high speed, its inertia is greatly increased. This causes the flywheel to remain stationary within the gyro gimbal structure.
To align the gyroscope flywheel to the local earth gravity vector (downward pull of gravity) a pendulum sensor is attached under the spinning flywheel. In operation, the pendulum is held suspended within a magnetic sensor with the magnetic sensor measuring the difference between the pendulum axis and the spin motor axis.
The sensor output is amplified and used to drive a torque motor that causes the gyro flywheel to rotate in a direction to reduce the sensor output. In actual operation, the pendulum sensor is affected by lateral accelerations that cause it to oscillate about true position.
To correct for this oscillation, the gyro circuit’s time constants are long. The long time constants cause the gyros flywheel to ignore periodic variations of the pendulum and align itself to the average pendulum position. Figure 2-18 shows the essential elements of the gyro.
Figure 2-18.-Vertical gyro, schematic diagram. 2-21 UNCLASSIFIED
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2.1.4 Cell Alignment For a pilot to use the SGSI for an accurate landing, the cell (Figure 2-19) must be properly aligned. There are two adjustments necessary for this alignment. One adjustment is focusing the cell and the other is setting the beam angle in reference to the GSI base plate.
Figure 2-19.-Glide Slope Indicator.
Cell Focusing As shown in the simplified cell schematic, figure 2-20, you can see that by moving the light mask into or away from the colored filter changes the sensitivity of the cell. The sensitivity can be defined as how fast the light bar will appear to move in the cell as an observer traverses from the bottom to the top of the cell. If the light mask is close to the colored filter, the sensitivity is decreased and the angle that a viewer would move through in going from the bottom to the top of the cell is increased. If the light mask is moved away from the colored filter, the sensitivity is increased and the angular coverage of the window decreases.
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Figure 2-20.-Simplified cell schematic.
Thus, the cell can be focused and the sensitivity set by moving the light source and slots in relation to the colored filter (fig. 2-21). In the GSI cell, the distance from the slots to the Fresnel lens is 16.8 inches. The cell is calibrated so the 1-inch amber section of the lenticular lens is exactly 1 degree of arc. A typical cell calibration setup is shown in figure 2-22.
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Figure 2-21.-Glide slope indicator, simplified functional diagram.
To focus the cell, it must be placed on a level plate and two screens 10 feet (±1/8 inch) apart must be set up in front of the cell (see fig. 3-18). Turn the cell on and measure the height of the amber at screen one and subtract it from the height of the amber at screen two (fig. 2-22). If the cell is properly focused, the difference should be 2-3/32inch±1/8 inch. A dark band will appear between each of the colors due to light scattering at the interface; this band should be split evenly to obtain height measurements.
Figure 2-22.-Typical cell calibration setup (overhead view). 2-24 UNCLASSIFIED
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Figure 2-23.-Cell focusing measurements.
Beam Angle The angle of the light beam to the horizon must be accurate and remain constant so a pilot may maintain a fixed rate to the ship. The glide slope angle is set using the degree plate on the right side of the cell and is checked on-the platform by means of pole checks to ensure the proper settings.
At the same time the cell is focused it can be calibrated for proper glide slope. Referring to figure 2-23, you can see that the same screen arrangement can be used for measuring the angle of the red/amber inter- face.
Set the baroscope supplied with the system on top of the level plate and mark off a reference mark on each screen. Adjust the cell glide angle using the knurled knob under the lamp housing until the difference between the reference mark on the red/amber interface on screen two is equal to 6-9/32 inches ±7/32 inch. Drill and pin the degree plate so it indicates three degrees.
In this measurement, the cell should project the beam on the two screens and the center of the dark band between the red and amber filter should be used for all measurements.
The slot through which the light bar is formed determines the size of the light bar as it is viewed through the cell face. In this system, it is not adjustable.
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2.1.5 Thermal Control Temperature control of the GSI includes cooling of the projection lamp compartment and temperature regulation in the lens compartment. These are discussed in the following paragraphs.
Projection Lamp Compartment Cooling The three projection lamps used in the GSI generate large amounts of heat when they are operated at full intensity. Cooling of this compartment is accomplished by a blower/louver arrangement. A special design louver assembly is located on each side of the projection lamp shroud; this design allows entry of cooling air while maintaining a weather seal to keep moisture, dirt, and so on from entering. Cool air is drawn in through the rear louver by the blower fan, and exhausts through the side louver after absorbing heat radiated by the projection lamps.
Figure 2-24.-Projection Lamp Cooling Assembly.
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Lens Assembly Temperature Control Temperature control of the Fresnel/lenticular lens assemblies is important to prevent lens distortion fogging, or other environmental reactions. In the GSI, lens temperature control is achieved by blowers, heaters, and thermal switches.
The temperature control circuits (see figs. 2-25 and 2-26) are used to regulate operating temperatures in the GSI assembly. When power is applied at the remote control panel, voltage is applied to the heaters and blowers to the left and right of the lens assemblies. Blower motors B1 and B2 begin to operate as soon as voltage is applied. Control thermoswitches S1 and S2 are set at 100 +10°F. To keep this temperature constant, S1 and S2 open and close as the temperature rises and falls in the GSI assembly. As the thermoswitches open and close, power is removed from or applied to heaters H1 and H2. If S1 and S2 fail to open, backup thermoswitches S3 and S4 will open, preventing damage to the lenses. A simplified schematic of the cell wiring appears in figure 2-25.
Figure 2-25.-GSI cell, simplified schematic.
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Figure 2-26.-Cell power.
GSI Transformer The GSI uses three 21-volt 150-watt projection lamps for its light source. This is about 21 amps of current and would cause considerable voltage drop if long cables were used, thus the transformer assembly is mounted close to the GSI light and uses a fixed length of cable (10 feet) from the transformer secondary to the GSI cell connector. The system autotransformer supplying the primary voltage to the transformer is located in the remote control panel. A simplified schematic is shown in figure 2-26.
2.1.6 Stabilized Platform System The stabilized platform system is an electrohydraulic served platform used to stabilize the GSI against the ship’s pitch and roll. This keeps the tricolored GSI light at a fixed angle to the horizon. The stabilization is termed a one-to-one stabilization system. This means that for each degree of pitch or roll of the ship, the platform pitches or rolls an equal amount in the opposite direction. Thus, the platform remains level to the horizon or more precisely perpendicular to the local earth gravity vector.
Operational Modes
The system has four operational modes: Internal Gyro, Ship’s Gyro, Internal Gyro Stabilization Lock, and Ship’s Gyro Stabilization Lock.
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2.1.7 SGSI System Normal Operating Procedure Stabilization from the internal gyro is the normal mode of system stabilization and is preferred to ship gyro mode because of higher system accuracy and addition of the gyro failure alarm. The system should always be operated in this mode as opposed to ship gyro operation unless a system failure prevents it. Operating control is normally conducted from the remote control panel from which the operator can turn the system on and vary the intensity of the source light. The system may also be turned on at the electronics enclosure assembly when the POWER ON/OFF push button is depressed. Adjustment of the source light intensity, however, can only be adjusted at the remote control panel. The normal mode is the interred gyro mode, where the gyro acts as the system sensor detecting any deviations from platform level. In this mode the platform will always remain level and cannot be offset.
Internal Gyro Stabilization Lock Mode
The internal gyro stab-leek mode disconnects internal gyro signals from the stabilization loop and locks the platform in a neutral position for test, alignment, and troubleshooting purposes. The system must be set to internal gyro for internal stab-leek operation. While in this mode, the test switches and manual drive potentiometer can be operated to enable insertion of signals independent of the local gyro. This mode enables the operator to isolate and test various parts of the system while disabling other parts.
Ship Gyro Stabilization Mode Ship gyro stabilization is provided as an alternative to platform-mounted internal gyro stabilization. The system should be operated in the internal gyro mode unless component failure disables that portion of the circuitry since switching to the ship’s gyro reduces system accuracy. The internal gyro/ship gyro switch-indicator is on the component panel assembly. A ship gyro indicator on the remote control panel serves to remind system operators when the alternative stabilization source is in use.
Ship Gyro Stabilization Lock Mode
The ship gyro stabilization leek mode disconnects the ship’s gyro signals at the input to the gyro signal card assembly and replaces them with ground reference or manual drive potentiometer signals. This permits check-out and troubleshooting of ship gyro stabilization and stabilization error detecting circuitry. The internal gyro/ship gyro switch-indicator on the component panel assembly should be placed in the ship gyro position to enable the stabilized platform to track manual drive signals. The lamp control relay extinguishes GSI source lamps while operating in this stab-leek mode.
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Platform Configuration The stable platform consists of a flat top plate to which the GSI is affixed. The top plate is attached to the base plate through a universal joint and a center post and is moved by two hydraulic actuators that are coupled to the top plate with two axis rod ends. The universal joints and rod ends allow the platform to tilt in two axes. These are designated pitch and roll to match ship motions for which the platform compensates. Figure 2-27 illustrates the major components of the platform.
Figure 2-27.-Functional diagram of the stabilized platform assembly.
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2.1.8 Servo Loops To understand the system operation, you need to have an understanding of feedback control systems. A feedback control system is a system where an input signal is compared with the system output and an error signal is generated. This error signal is then amplified and used to drive the output in a direction to reduce the error.
Assuming the input and output pots are initially equal, then the difference in voltage is zero and there is no error. If the input command pot is moved, then an error is generated. The amplifier amplifies the error and drives the power actuator that moves the output pot in a direction to reduce the error. Thus, in a feedback system, the output can be made to follow the input. This type of feedback system is often referred to as a servo loop.
The GSI stable platform uses two servo loops in each axis, the gyro loop and the LVDT loop. In the gyro loop, the gyro is used as an error detector sensing the downward pull of gravity at its particular location. This is termed earth’s local gravity vector. The gyro lines itself up with this downward pull and any difference between the gyro case and its internal reference provides an output. This output is used as an error signal to correct the platform top to earth level.
The LVDT loop is quite similar to the gyro feedback loop, only the sensor is changed. Figure 2-28 shows that the LVDT is mechanically connected to the actuator to sense its position pot. The feedback signal from the LVDT is connected to the error detector. The LVDT has as its input either zero (stab-lock) or a signal from the manual position pot. With the manual position pot switched out of the circuit, the input to the error detector is zero (ground). The LVDT is adjusted so its output is zero when the platform top is level to its base, thus errors are only generated when the LVDT has an output and these are amplified and drive the output to zero. In operation, any voltages measured in the servo loops are small and are proportional to the system error. The complete system servo feedback loop (single channel) is shown in figure 2-29. This incorporates both the gyro and stab-lock loops and the switching between them.
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Figure 2-28.-LVDT servo loop.
Figure 2-29.-Stabilization circuits, block diagram.
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2.1.9 Operational Amplifiers Operational amplifiers (op-amps) are used throughout the stable platform system as amplifiers, oscillators, and comparators. To understand the different circuits, you need to have a basic understanding of op-amps. An operational amplifier is a high gain (10,000 or greater), highly stable, dc amplifier. It is used most often to perform analog computer functions such as summing and integration.
The op-amps used in this system are integrated circuit types using a configuration as shown in figure 2-30.
Figure 2-30.-Op-amp diagram.
An op-amp is a very high gain device, whose output is the amplified difference between the inverting and non-inverting inputs. If feedback is added, the op-amp will try to keep the voltage difference between the two inputs near zero.
The most common form of op-amp is the inverting amplifier, as shown in figure 2-31. With the non-inverting input tied to ground, the inverting input will be close to ground and is referred to as a virtual ground. The higher the amplifier gain, the closer the point will be to ground and for all computations it is assumed to be ground. If an input voltage (Vin) is applied to the circuit of figure 2-31, a current will flow in Rin. The amplifiers will amplify and invert the current and provide an output voltage. The output voltage will cause a current to flow in RF that will exactly cancel that flowing through Rin. If the currents do not cancel, the difference between them will be amplified until they do.
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Figure 2-31.-Inverting amplifier diagram.
Multiple input circuits are similar to the inverting amplifier circuit. The gain of each input is controlled by its input resistor and the feedback resistor with the inputs added.
No voltage greater than 15 volts should be applied to any pin of an op-amp or damage will result. The op-amps output is short-circuit protected; thus, shorting the op-amps outputs will not damage them. Op-amps exhibit three common types of failures: no output, saturated positive, and saturated negative. A saturated voltage is one that is maximum for a particular op-amp usually greater than 11 volts. Any op-amp whose output is greater than 11 volts and does not change with varying inputs may be defective. Check for large inputs and open feedback resistors before replacing the op-amp.
2.1.10 System Electronics The GSI system electronics is divided into 13 fictional areas as follows:
• Gyro demodulator • LVDT • LVDT demodulator card • LVDT oscillator • LVDT demodulator • Servo amplifiers • Dither oscillator • Error circuit • Gyro alarm circuits • Gyro signal card • Source light failure detector • Power distribution circuits
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Gyro Demodulator The gyro demodulator is a non-repairable item. The gyro demodulator receives 115-volts ac, 400-Hz reference signals from stator leads S1 and S3 of the pitch and roll synchros in the gyro. The demodulator converts the ac synchro signals to dc with the in-phase ac signal positive and the out-of-phase signal being negative. This type of demodulator is called a phase-sensitive rectifier. For an in-phase signal, the device behaves as a bridge rectifier with a capacitor filter to remove ripple.
The internal gyro synchros that feed the demodulator are excited with 26 volts ac, 400 Hz and have a maximum output between S1 and S3 of 11.8 volts ac at ±90° rotation. When the signals are demodulated by the gyro demodulator, the output is ±10 volts dc at ±90° of rotation from horizontal.
Linear Voltage Differential Transformer
The LVDT is an ac electromechanical transducer that converts physical motion into an output voltage whose amplitude and phase are proportional to position.
In operation, an ac excited primary winding is coupled to two secondary windings by a moveable core placed between them (fig. 2-32). Displacement of the core from its null position causes the voltage in one winding to increase, while simultaneously reducing the voltage in the other winding. The difference between the two voltages varies with linear position.
Figure 2-32.-LVDT amplified schematic.
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LVDT Demodulator Card The LVDT demodulator card supplies a constant voltage ac excitation to the LVDT primaries and converts the pitch and roll LVDT amplitude and phase signals to a variable dc voltage. This is accomplished in three separate circuits: the LVDT oscillator and the pitch and roll demodulators.
LVDT Oscillator The LVDT oscillator consists of a quadrature oscillator and a power amplifier. The quadrature oscillator is used to generate a constant-amplitude, constant frequency sine wave. The power amplifier is a low output-impedance driver used to power the LVDT primaries and the pitch and roll demodulator diode switches.
To understand the operation of the quadrature oscillator, assume capacitor C3 of figure 2- 33 is initially charged positive. The non-inverting integrator IC3-1 will charge C1 so its output goes positive. This positive voltage will cause the inverting integrator IC3-2 to charge its capacitor C2 and its output will go negative. This negative voltage will discharge C3. This will continue until C3 is charged negative and then reverse, causing the circuit to oscillate. The zener diodes clamp the output and stabilize the amplitude so the output voltage is a stable 6.5 volts ac.
Figure 2-33.-LVDT quadrature oscillator. 2-36 UNCLASSIFIED
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LVDT Demodulator The pitch and roll LVDT demodulator are identical except for their gains. They are called phase sensitive demodulators. The input to the demodulator is a variable-voltage, variable-phase signal from the LVDT. This signal is full-wave rectified and filtered and its output polarity is positive for signals out of phase with the reference and negative for signals in phase.
Servo Amplifiers
The pitch and roll servo amplifier circuit cards are identical except for the gains and servo compensation. Three inputs are summed into amplifier A1: LVDT, gyro/manual control, and rate gyro. In normal operation, only gyro signals are used. In stab-lock mode, the LVDT signal is the input with manual control being used for testing. Figure 2-34 shows a schematic diagram of the pitch servo amplifier card.
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Figure 2-34.-Pitch servo amplifier card assembly (F102), Schematic diagram.
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Dither Oscillator The dither oscillator provides a high-frequency (compared to system response) signal to the servo valves to keep them in constant motion to prevent sticking at null.
The dither oscillator is a phase shift oscillator. It depends on the phase shifts inherent in RC networks to shift the phase of the amplifier feedback 180°. This will cause a sustained oscillation if the amplifier gain is high enough. The gain also determines the quality of the sine wave.
Error Circuit Card
The error circuit card is used to monitor the pitch and roll servo errors. It allows monitoring of the gyro’s internal pendulum reference for test purposes. Since the system is not perfect, servo errors are present. Voltages representing system errors are compared with a reference voltage that represents the maximum allowed system error. If it is exceeded the system will go from ready to not ready and turn out the GSI light. System errors existing during turn-on would trigger a false not ready light. To prevent this, a delay is included in the error circuit.
A schematic of the error circuit is shown in figure 2-35.
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Figure 2-35.-Error Circuit Schematic Diagram.
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Gyro Alarm Circuits The SGSI system incorporates an independent failure detection circuit that detects any failure that will result in a loss of stabilization. It does this by comparing an input from the ship’s gyro with the output of the platform LVDT. When the system is operating correctly in the internal gyro mode, the output of the LVDTs is directly proportional to the ship’s motion. If the ship’s motion from the LVDTs is out of phase (reverse polarity) to the ship motion from the ship’s gyro, the two will cancel. Any voltage left over from the summation will be the error between the ship gyro and the platform. The error is compared against a preset limit, and if it exceeds this limit the platform error relay is tripped. The ship gyro input is required for the gyro alarm and is also used for ship gyro stabilization and for the rate lead. The rate lead circuits are used to reduce velocity lag of the platform and increase system dynamic accuracy. In the ship gyro stabilization mode, the system operates at a reduced accuracy due to null errors and LVDT linearity error. Therefore, the ship gyro mode is to be used as a backup mode only. Figure 2-36 shows a simplified diagram of the gyro alarm circuits.
Figure 2-36.-Gyro alarm circuits – signal flow.
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The gyro alarm failure alarm circuit can be disabled by pushing the gyro alarm OFF push button. This supplies +15 volts dc to one side of the error relay and effectively disconnects the gyro failure alarm circuits. In addition an interlock circuit prevents unwanted platform oscillation when the alarm circuit is not actuated.
Gyro Demodulator Board The gyro demodulator board contains a synchro to dc converter and a gyro error detector circuit. The F110 and F111 are identical cards: one is used in the pitch channel and the other in roll. The synchro to dc converter is a sealed module not repairable by shipboard personnel.
Gyro Error Detector Circuit The gyro error detector circuit consists of a precision full wave rectifier, a filter, a voltage comparator, a transistor, and a relay. The input signal to this card is the summation of the ship’s gyro and the platform LVDTs.
Gyro Signal Card Assembly The gyro signal card (F106) amplifies and sums the demodulated pitch and roll synchro signals from the ship’s gyro with the platform LVDT outputs. It also provides offset adjustments to make up for any difference in alignment between the ship’s gyro and platform. In addition, rate lead signals are derived by differentiating the ship gyro signals.
Source Light Failure Detector The source light failure detector is a circuit that monitors the voltage and current going to the three source lights. When one or more of the source lamps fail, the source light failure indicator on the remote panel is illuminated.
Power Distribution Circuits The system requires two power sources from the ship 440-volts ac, 60-Hz, 2.7-amp power for the pump and 115-volts ac, 60-HZ, 15-amp power for the rest of the system. In standby (system circuit breaker on), the system heaters and standby lights are on. When the POWER ON push buttons are depressed, the internal power supplies are energized except for the ±15 volts dc. The ±15 volts dc supply is energized after the time delay relay has timed out, the hydraulic pump is running, and system hydraulic pressure is normal. Then, the hydraulic pressure switch is actuated.
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2.1.11 Hydraulic Components The SGSI system uses hydraulic pressure for motive power. A constant-pressure, variable-delivery hydraulic pump supplies hydraulic pressure. Pressure fluctuations are dampened by accumulators. The fluid is gaited by servo valves into either side of the hydraulic cylinders. The fluid pressure then causes the cylinders to move the platform.
The hydraulic system is sensitive to dirt and other contaminants. Therefore, care must be used when adding fluid or opening any part of the hydraulic system.
Refer to the hydraulic pump assembly shown in figure 2-9 when studying the following paragraphs.
Hydraulic Accumulator
The hydraulic accumulators used in this system are steel cylinders with internal rubber bladders. Before putting the accumulators in service, the bladders are pressurized with dry nitrogen to 700 psig for the high--pressure accumulator and 38 psig for the low- pressure accumulator.
When hydraulic pressure is applied, the accumulator fills with fluid and the bladder is compressed until the dry nitrogen charge pressure equals that of the hydraulic system. In this system, it is 1400 psig. Because of the bladder compression, the accumulator will absorb pressure fluctuations and prevent hydraulic hammer. If the system momentarily requires a higher flow than the pump will supply, the accumulator will provide it and be recharged when the demand has passed.
Hydraulic Cylinder
The hydraulic cylinders used in this system are linear actuators. Hydraulic fluid gated by the servo valve will push the piston in either direction. The hydraulic pressure exerted by the piston is 1400 psig in extension and 700 psig in compression. Extreme care must be exercised when working on the system due to the amount of force available.
The cylinder is an inherently reliable device requiring little maintenance in normal use. However, the only required maintenance is cleaning dirt and grit off the actuator rod and tightening the packing gland nut if a leak develops. Do not over tighten the gland nut or the packing will bind on the rod, causing the cylinder to chatter in operation. If cylinder replacement becomes necessary, the defective cylinder must be returned through supply charnels for overhaul.
System low-amplitude vibration, or chatter in some cases, may be traceable to cylinder internal binding; in which case the cylinder should be replaced.
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Servo Valve Servo valves are commonly used in closed-loop servo systems. They control the flow of fluid to or from the load actuator in proportion to the impact current signal to the valves’ torque motor.
Hydraulic Pump The hydraulic pump used in this system is a constant-pressure, variable-delivery pump. It is similar to a constant voltage source in which current will vary upon demand. Referring to figure 2-9, hydraulic fluid is gravity fed from the reservoir to the pump unit through the pump case fill piping to ensure that the pump case is full at all times, thus keeping air out of the line. The motor-driven pump draws fluid through a suction strainer, located in the reservoir, into the pump where it is pressurized to 1400 psi and applied to the hydraulic pressure line. A fluid flow filter removes solid impurities greater than 3 microns in size. In the event the filter becomes clogged, it is bypassed. The filter output then flows past the pressure gauge, the pressure switch, and the bypass valve. The pressure gauge should indicate 1400 psi in normal operation, and the pressure switch should be closed for pressures above 1200 psi. The bypass valve is normally closed and will open only if the pressure exceeds 1800 psi.
If the pump is operating normally, the bypass valve will be closed and the fluid will flow through the check valve and out the gate valve to the system. The check valve is a one- way valve. The fluid returning from the system flows through the return gate valve and check valve into the reservoir. The return check valve only allows fluid to flow in one direction and requires 75 psi of pressure before it will open. This maintains the return line pressure at 75 psi.
For the pump, heater, and overtemperature switch to operate properly, the fluid reservoir must be properly filled. Too little fluid may actually cause the pump to overheat.
Pump Motor Contactor
The motor controller usually has 440 volts ac applied to it. The pump is actuated by applying 115 volts ac to the motor controller relay. The pump motor is protected by thermal overloads, located in the motor controller. A thermal overload is a relay that is actuated by heat. Motor current flows through a low-value resistor, generating a small amount of heat. If the current increases beyond a specified value (3.7 amps), the heat generated will melt a solder bond on a ratchet wheel, which holds back a spring-loaded relay. This will cut the pump power by opening the circuit to the motor control relay. The thermal relay should then be allowed to cool before pushing the reset button on the pump controller.
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The pump motor is factory wired for 440-volts ac operation and should not be changed as the motor controller current limits are set for 440-volts ac operation.
Hydraulic Fluid Heater The fluid heater is a 175-watt immersion-type heater. The fluid must be kept at approximately 70°F or greater to prevent it from becoming too viscous and causing servo errors. The heater is a Calrod type with a built-in thermostat. The thermostat is normally factory set but may be adjusted if necessary. To adjust the heater, unscrew the cover plate by turning counterclockwise and use the internal screwdriver adjustment to set the temperature. It will take about a half hour for the temperature to stabilize.
Overtemperature Switch
The overtemperature switch is a mechanically adjustable immersion-type thermoswitch. It is used to indicate overheating of the pump oil. It does not indicate a direct failure. In a warm environment of approximately 85°F the oil temperature will be about 120°F. An increase in oil temperature will most likely be due to increased fluid viscosity or a clogged pump filter. If this is the case, the pump should be drained and flushed with warm water, and the fluid and filter replaced.
Hydraulic Pressure Switch
The hydraulic pressure switch is a single-pole, double- throw, pressure-actuated switch. It is used to turn on the system electronics when there is enough pressure to stabilize the system. It is normally set to actuate at 1200 psi.
The pressure switch is adjusted by turning the label until the inner body is exposed. It can be turned with a screwdriver or other instrument inserted in the inner body holes. The pressure switch setting is decreased by turning the inner body counterclockwise as viewed from the connector end.
The hydraulic pressure switch is a non-repairable item that must be replaced if it is not operating properly.
2.2.0 HORIZON REFERENCE SET (HRS) The Horizon Reference Set (HRS) is normally maintained by the Ship’s Electrician Mates. This brief discussion is provided due to the HRS’s interface with various IC systems.
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2.2.1 Helicopter/Ship Interface Air capable ships usually include a flight deck and hangar enclosure at the aft end. The flight deck accommodates helicopters but with minimum all-round clearance.
When the helicopter is hovering above the flight deck prior to landing, the helicopter pilot might experience considerable judgment difficulties. These are due to the rolling and pitching motions of the ship. Therefore, these flight deck facilities are frequently expanded to include a Horizon Reference Set (HRS) and a Recovery Assist, Secure and Traverse (RAST) System.
The HRS is incorporated in the hangar and flight deck locations of air-capable ships. The HRS consists of three separate units, shown in Figure 2-37. They function together to provide a stable, external, visual, horizon reference as a pilot aid during helicopter deck landings. The reference is in the form of a horizontal bar assembly fitted with electroluminescent panels along its full length. The HRS is of significant importance to level flight: especially during inclement weather; at night when the true horizon is obscured; and whenever the flight deck is rolling.
The other component associated with flight deck landings is the RAST system. The RAST system is incorporated in the flight deck of helicopter-equipped ships. The recovery assist portion of the system enables the ship's helicopter to land safely on the flight deck particularly during adverse weather conditions. It also secures the helicopter after landing. This prevents equipment damage during extreme movements of the ship.
Shipboard helicopters are modified to utilize the shipboard RAST system. Helicopter modifications include a main probe and messenger winch, a retractable tail probe, and associated pilot controls.
When the helicopter lands, it is imperative that the recovery takes place at the same location every time. During the ship's forward motion and particularly during adverse weather conditions, when the ship is subjected to violent rolling and pitching motions, the RAST system assists in aligning the helicopter during descent.
During the final approach to landing and when the helicopter is tethered to the ship while hovering, level flight must be maintained. The horizon reference is located on the hangar structure. There it can be observed during the pilot's visual structure clearance scan.
The HRS requires two sources of ship's power to energize it. These supplies are connected to the Electronic Components Assembly (ECA).
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The roll angle of the lamp panel and bar assembly (LPBA) is derived from a synchro signal. This signal is obtained from the ship's vertical gyro reference system. The input signal is connected to the ECA.
Figure 2-37.-Horizon Reference Set. 2-47 UNCLASSIFIED
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2.2.2 Safety Features The HRS is equipped with an automatic fault detection .system which:
a. lights a red warning lamp if the horizon reference is faulty;
b. moves the LPBA to the 00 roll position, if possible, if a fault occurs;
c. shuts down the system.
The HRS shuts down in anyone of three modes. These modes depend upon either the type of fault condition or if the shut-down is initiated by the operator. The specific shut-down modes are:
Soft. This mode results in the LPBA returning to the 00 roll position, if possible, before being locked by the brake. The electroluminescent lamps on the LPBA are turned off immediately. The warning lamp is lit immediately. This mode occurs if there is > 20 difference between the true horizon and the LPBA reference. The> 20 difference must have been sustained for 2 seconds and within the normal operating roll angle limits of the LPBA.
Hard. This mode results in the LPBA being locked by the brake in its present position. The electroluminescent lamps are turned off immediately. This mode occurs if there is a partial or complete failure of the external 400 Hz power, internal DC power supplies or input gyro reference signal. For these failures, the warning lamp lights immediately. A hard shut-down can also be initiated by the operator. This is accomplished by pressing the RESET push-button on the active control station. In this case, the warning lamp does not light.
Normal. This mode results in the LPBA returning to the 00 roll position before being locked by the brake. The electroluminescent lamps are turned off immediately. The warning lamp does not light. This mode is initiated by the operator when the STOP pushbutton is pressed on the active control station.
2.2.3 Equipment Description The HRS comprises three separate units interconnected electrically:
a. Indicator, Stabilization Data (ISO).
b. Control-Indicator (CI).
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2.2.4 Indicator, Stabilization Data (ISD) The ISO comprises three sub-units: the housing, the LPBA and the warning lamp. They are located centrally on top of the hangar structure at its aft end.
Housing. This unit contains the electromechanical drive. The drive positions the LPBA so that it remains parallel to the natural horizon. The electrical control system rotates the LPBA in the direction which counteracts the roll of the ship to provide the true horizon reference. The unit includes monitoring sensors which measure the LPBA roll angle relative to the housing.
The unit also includes electrical limit switches. These switches drive the LPBA back into its roll operating range if the electronic limits fail. Mechanical stops in the unit prevent the LPBA from hitting the ship's superstructure if the electrical limit switches fail. The unit also supports the warning lamp which indicates system failure. The housing is mounted on a pedestal. This allows clearance for the LPBA to travel through its complete operating arc (approximately ± 40° from the horizontal) without hitting the superstructure.
Lamp Panel and Bar Assembly (LPBA). The gyro-stabilized LPBA which is 10ft long provides a visual horizon reference for the helicopter pilot. The bar provides a stable external horizon reference continuously to the pilot of the helicopter which is approaching and landing on the flight deck. This is desirable, particularly at night. The bar is illuminated throughout its length by green, electroluminescent panels. The illuminated bar is visible in the same plane of vision as seen by the helicopter pilot when conducting the normal obstruction clearance scan. Bar rotation is defined as cw or ccw when facing the electroluminescent panels.
When the bar is parallel to the ship's deck, it is referred to as being in the 0° roll position. It should be noted that the horizon reference applies only to the lateral roll axis of the ship. The horizon bar provides a reference of the true horizon which is independent of the ship's rolling motion. The bar does not provide a reference for judgment of the ship's pitching motion or pitching of the helicopter. Furthermore, although the true horizon reference is provided continuously, the bar and housing are secured to the ship's structure.
Therefore, they are not restrained from movement (i.e. displacement) in the ship's rolling plane. The pitching and displacement motion of the ship occurs at a much slower frequency than the roll. Therefore, these motions do not impact helicopter operation significantly.
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Warning Lamp. The warning lamp is attached to the top of the housing. It consists of six incandescent lamps covered by a red lens. The warning lamp lights to warn the pilot of an approaching helicopter if there is a fault in the HRS.
2.2.5 Control-Indicator (CI) The CI contains HRS power and operating controls, and also status indicators. These controls and indicators are duplicated in the ECA however the CI has primary control with override capability. The CI is located in the vicinity of the helicopter control station.
2.2.6 Electronic Components Assembly (ECA) The ECA contains all the electronic servo control circuitry, primary power, signal and operating controls and adjustments. Its principal function is to provide electrical signals to drive the bar assembly to the correct roll position. The ECA is located typically in the flight control area.
2.3.0 WAVE-OFF LIGHT SYSTEM FOR AIR CAPABLE AND AMPHIBIOUS AVIATION SHIPS This section contains information describing each assembly of the Mk 1 Mod 0 Wave-off Light System (Figure 2-38). Information is also provided which will enable operating personnel to prepare and operate the Wave-off Light System. The information provided in this section is presented under the following topics:
1. Purpose of Wave-off Light System.
2. Physical description.
3. Operating instructions.
2.3.1 Purpose of Wave-Off Light System The Wave-off Light System is an electronic system designed for use on aviation facilities ships. Two wave-off lights are installed one on each side of the stabilized platform. These wave-off lights provide a visual indication, which when flashing, informs the helicopter pilot that he is to abort the landing attempt and initiate a new landing approach.
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Figure 2-38.-Wave-Off Light System.
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2.3.2 Physical Description The assemblies that comprise the Wave-off Light System together with their unit numbers are as follows:
1. Master control panel assembly (GI00)
2. Remote panel assembly (G200, G200A)
3. Junction box assembly (G400)
4. Wave-off light assembly (G500, G500A)
2.3.3 Technical Characteristics The technical characteristics of the Wave-off Light System are listed in Table 2-1.
MODE CHARACTERISTIC Light Intensity Adjustable from a variable minimum brightness to 100%. Flash Rate Variable rate at 50% duty cycle. Preset at 90 flashes/min. Wave-Off Initiation Activated with flash indication from the master control panel and remote panels. Wave-Off Monitor A “positive” indicator, sensing voltage to the lamps, flashes when the wave-off lights are operable.
Table 2-1.-Technical Characteristics.
2.3.4 Input Power Requirements The power required to operate the Wave-off Light System is supplied from the ship's emergency power supply. The amplitude and frequency of the 115-volt, 60Hz, 7.5ampere source (ungrounded) must be regulated to within 10 percent.
2.3.5 Master Control Panel (G100) The master control panel (Figure 2-39) is signal processing, distribution, and control center for the Wave-off Light System. The panel has a removable cover which protects the panel controls from moisture and dirt.
Lowering the panel face plate provides access to the card cage assembly, which holds the monitor, flasher/driver and extender cards, the step-down transformer (115/55 vac), and the terminal boards used for system interconnecting wire terminations.
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Figure 2-39.-Master Control Panel Assembly (G100).
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2.3.6 Remote Panel Assembly (G200, G200A) There are two remote panels (see Fig. 2-38) used in the wave-off system. The panels are identical except the lone located at the Helo Control Station (G200A) has a moisture and dust-proof removable cover. Figure 2-40 describes the function of the remote panel controls and indicators.
Removal of the panel face plate provides access to the dimmer board assembly and the terminal board used for system interconnecting wire connections.
Figure 2-40.- Remote Panel (G200 and G200A) - Controls and Indicators. 2-54 UNCLASSIFIED
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2.3.7 Junction Box Assembly (G400) The junction box assembly (see Fig. 2-38) is a moisture and dust-proof unit which provides a means to connect the cable from the master control panel with the wave-off light cables. It is located with the wave-off light assemblies.
2.3.8 Wave-Off Light Assembly (G500, G500A) The wave-off light assemblies (see Fig. 2-38) are identical units, which are installed one on each side of the stabilized platform. System interconnecting cabling connects to each light by way of a connector located at the rear of each lamp housing. This connector has a cover, attached with a retaining chain, which is used to prevent moisture and dirt from entering the connector when the interconnecting cable is not attached.
2.3.9 Operating Instructions Information is provided for operating the Wave-off Light System in normal and remote operational mode. This information is presented under the following topics:
1. System controls, indicators, and fuses.
2. Safety precautions.
3. System initial control settings.
4. System turn-on procedure.
5. System normal and remote operation modes.
6. System turnoff procedure.
2.3.10 System Controls, Indicators and Fuses The information necessary to familiarize personnel with the operating controls, indicators, and fuses is presented in Figures 2-41 and 2-40. The information provided in these figures and tables will enable personnel to locate, identify, and understand the function of each component listed.
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Figure 2-41.- Master Control Panel (G100) - Controls and Indicators (Sheet 1 of 2).
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Figure 2-41.- Master Control Panel (G100) - Controls and Indicators (Sheet 2 of 2).
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2.3.11 Safety Precautions The safety precautions given in the following warning are to he strictly adhered to by all personnel coming in contact with the wave-off system.
WARNING Voltages which are dangerous to life are used in the Wave-off Light System. Before applying power to the Wave-off Light System, all covers and panels must he secured.
2.3.12 System Initial Control Settings Information concerning the proper initial control settings and the preferred order in which to make these settings is provided in Table 2-2.
ASSEMBLY CONTROL POSITION Master Control Panel (G 100) SYSTEM CIRCUIT BREAKER REMOTE OVERRIDE SWITCH WAVE·OFF INTENSITY PANEL ILLUMINATION OFF Normal Set at 50% Full CW (maximum intensity) Remote Panel (G200 and G200A) INTENSITY Full CW (maximum intensity) Table 2-2.- System Initial Control Settings.
2.3.13 System Turn-On Procedure The system turn-on procedure, which is performed after the controls are initially set, is accomplished by following the steps as outlined in Table 2-3.
2.3.14 System Normal and Remote Operation Modes At the completion of the turn-on procedure, as described in Table 2-3, the Wave-off Light System is in the normal mode of operation. In the normal mode of operation, wave-off may be initiated from I anyone of three locations. They are: master control panel and remote panels (G200 and G200A).
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STEP ASSEMBLY CONTROL SETTINGS AND INSTRUCTION NORMAL INDICATION 1 Master Control Panel (G1OO). Place SYSTEM CIRCUIT BREAKER in ON position. SYSTEM ON indicator lights. Panel illumination lamps light. At Remote Panel G200 and G200A: SYSTEM ON indicator lights. 2 Press WAVE-OFF SWITCH. NOTE Prior to incorporation of SOSI and WOLS SIC 32, Rev A, wave-off may he initiated from either of the remote panels, not available after this SIC is incorporated. Master panel WAVE-OFF indicator flashes. NOTE When wave-off is initiated from either the remote panels or the portable switch, the respective location indicator on the master control panel will illuminate. At Wave-off Light: Wave-off lights flash. At Remote Panel: WAVE-OFF indicator light flashes. 3 Adjust WAVE-OFF INTENSITY control At Wave-off Lights: Wave-off lights vary intensity 4 Press wave-off switch Wave-off lights will extinguish.
Table 2-3.- System Turn-On Procedure.
The remote override mode of operation is used when wave-off initiation from a remote location is to be prevented or overridden. To place the system in the override mode of operation, raise the switch guard on the REMOTE OVERRIDE SWITCH (2, Figure 2- 41) and place switch SW2 in the "UP" (override) position.
The remote panel wave-off switches are now out of I the circuit; however, wave-off may still be initiated from the master control panel.
To remove the system from the remote override mode, press switch SW 2 "DOWN" and lower the switch guard. 2-59 UNCLASSIFIED
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2.3.15 System Turnoff Procedure When helicopter operations are complete, refer to the following for proper Wave-off Light System turnoff procedures.
1. Remove wave-off system from the flash mode by pressing the wave-off switch that originally initiated the wave-off.
NOTE
The switch which initiated the wave-off will be indicated by its respective indicator on the master panel.
2. Place the SYSTEM CIRCUIT BREAKER on the master control panel in the "OFF" position.
2.4.0 WAVE-OFF LIGHT SYSTEM MK 1 MOD 0 FOR LAMPS MK III EQUIPPED SHIPS The wave-off system for LAMPS Mk III equipped ships functions fundamentally the same as the Mk 1 Mod 0 described in the previous section. However, there are subtle differences which are described in this section. The primary difference is the interface with other shipboard systems. (For an overall system illustration, see figure 2-42.)
2.4.1 Interface with other Systems The Wave-off Light System MK 1 MOD 0 is interfaced with the Flight Deck Status and Signaling System (FDSSS) and Recovery Assist, Secure, and Traverse (RAST) Systems. The Deck Status Lights are also tied in with the overall operation. See block diagram figure 2-43. The Wave-off Light System Master Control Panel is interconnected to the FDSSS Interface Control Unit.
The Wave-off Light System and the FDSSS System are installed aboard air capable ships equipped for LAMPS Mark III operations. The FDSSS System enables the Helicopter Control Officer (HCO), at the Helicopter Control Station (HCS), to request and receive launch and recovery authorization from the Bridge and/or CIC. The FDSSS also incorporates control of the deck status lights at the (HCS) and provides status indications at the Bridge and CIC. Capability 10 control the wave-off lights via the Wave-off Lights System is incorporated in all units, except from the bridge and/or CIC units.
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Figure 2-42.- Wave-off Light System MK 1 MOD 0 for Lamps MK III Equipped Ships.
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Figure 2-43.- Wave-off Light System and interface - Block Diagram.
The FDSSS consists of an Operations Request Panel located at the Helicopter Control Station (HCS); two (2) Response Panels, one each located at the Bridge and CIC and an Interface Control Unit. Location of the Interface Control unit is at an accessible convenient location, central to Response Panels, Operations Request Panel, and Wave-off Light System Master Control Panel. Selection and request of an operating function may also be originated by the Landing Signal Officer (LSO) at the RAST Control Station. The FDSSS, RAST, and Deck Status Light are not considered to be components of the Wave- off Light System described in this section and are assumed to be installed aboard all LAMPS MK III equipped ships.
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2.4.2 Principal of Operation The Wave-off Light System indicates when a dangerous or potentially dangerous situation exists and the helicopter should abort its approach. The wave-off lights are installed on either side of the stabilized glide slope indicator and located parallel to the approach line on single-approach ships. The wave-off lights flash at 90 flashes per minute and are variable in intensity. In addition to providing the lamp flasher, a monitor circuit is incorporated into the system. It senses wave-off lamp voltage and wave-off command locations. This information is then displayed on the master control panel. Additionally, the wave-off indications are transmitted to the FDSSS and RAST Control Panel.
The monitor card receives all the wave-off commands from the FDSSS and RAST Control Panel and drives Master Control Panel lamps to indicate which switch was pushed. It also drives the panel dimmer, provides a wave-off output to the flasher/driver card, senses voltage across the wave-off lamps, and provides a positive indication of a wave-off at all panels.
Because of the interrelationship of the Wave-off Light System with the FDSSS, RAST, and Deck Status Light, pertinent interface data is included.
2.4.3 Wave-Off Light System Controls, Indicators and Fuses Controls, indicators, and fuses located on the Master Control Panel (G100A) are shown and listed in figure 2-44. This information will enable maintenance personnel to locate, identify, and understand the function of the Wave-off Light System.
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Figure 2-44.- Master Control Panel (G100A) - Controls and Indicators (Sheet 1 of 2).
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Figure 2-44.- Master Control Panel (G100A) - Controls and Indicators (Sheet 2 of 2).
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2.4.4 Safety Precautions The safety precautions given in the following warning are to be strictly adhered to by all personnel coming in contact with the wave-off system.
WARNING Voltages which are dangerous to life are used in the Wave-off Light System. Before applying power to the Wave-off Light System, all covers and panels must be secured.
2.4.5 Wave-Off Light System Operation
INITIAL CONTROL SETTINGS Information concerning the Wave-off Light System initial control settings and the preferred order in which to make these settings is provided in table 2-4.
STEP CONTROL POSITION MASTER CONTROL PANEL (G100A) 1 SYSTEM CIRCUIT BREAKER (CB-1) OFF 2 REMOTE OVERRIDE SWITCH (SW-2) Normal 3 WAVE-OFF INTENSITY (R-l) Set at 5 (Midpoint) 4 PANEL ILLUMINATION (R-2) Set at 10 (Full clockwise, for max. intensity)
Table 2-4.- Wave-off Light System -Initial Control Settings.
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TURNON PROCEDURE The Wave-off Light System turn-on procedures, performed after the controls are initially set, is accomplished by following the steps outlined in table 2-5. The system is then ready for operation.
STEP CONTROL SETTINGS AND INSTRUCTIONS NORMAL INDICATION Master Control Panel (G100A) 1 Place SYSTEM CIRCUIT BREAKER in ON position. SYSTEM ON indicator lights
Panel illumination lamps light 2 Press WAVE-OFF SWITCH
NOTE
Wave-off may also be initiated from FDSSS and RAST systems. Master Control Panel WAVE-OFF indicator flashes
NOTE
When wave-off is initiated from a point other than the Master Control Panel, the respective location indicator on the Master Control Panel will illuminate.
Wave-off Lights (G500 and G5OOA) flash 3 Adjust WAVE-OFF INTENSITY control. Wave-off Lights (G500 and G500A) vary intensity. 4 Press WAVE-OFF SWITCH Wave-off Lights extinguish.
Table 2-5.- Wave-off Light System -Initial Control Settings.
2.4.6 Normal and Remote Operation Modes
Normal Operation Mode At the completion of the turn-on procedure, the Wave-off Light System is in the normal mode of operation. When in the normal mode of operation, wave-off may be initiated from any one of following locations:
a. Master Control Panel (G100A) at the HCS.
b. FDSSS Operations Request Panel at the HCS.
c. RAST Control Console at the LSO Station.
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Remote Override Mode When the remote override mode of operation is used, wave-off initiation from a remote location is prevented or overridden. To initiate the override mode, lift the switch guard on the REMOTE OVERRIDE SWITCH (2, figure 2-44) and place switch in the "UP" (override) position. The remote switches are disabled (out of the circuit); however, wave-off can be initiated at the HCS by depressing the WAVEOFF SWITCH (6, figure 2-44) located on the Master Control Panel (G100A).
To return the system to the normal mode, raise the switch guard on the REMOTE OVERRIDE SWITCH and set switch to "DOWN".
2.4.7 FDSSS and RAST Systems Controls and Indicators Interfacing systems must be turned on and operational in order to initiate a remote wave- off. The Wave-off Light System is in the normal mode. Controls and indicators for the FDSSS and RAST systems, along with listings of their function are provided in figures 2- 45 through 2-47. An understanding of their normal function and operation is essential to personnel engaged in operation and maintenance of the Wave-off Light System.
Figure 2-45.- FDSSS Operations Request Panel - Controls and Indicators (Sheet 1of 3). 2-68 UNCLASSIFIED
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Figure 2-45.- FDSSS Operations Request Panel - Controls and Indicators (Sheet 2 of 3).
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Figure 2-45.- FDSSS Operations Request Panel - Controls and Indicators (Sheet 3 of 3).
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Figure 2-46.- FDSSS Bridge/ClC Response Panel - Controls and Indicators (Sheet 1).
ITEM NO.
NOMENCLATURE FUNCTION 1 Indicator - LAUNCH or RECOVER. LAUNCH or RECOVER light is illuminated and flashes red by a signal from Operational Request Panel or Rat Control Console. Lights glow steady extinguished when the OPERATIONS REQUEST selector (figure 2-45) is turned. 2 Indicator· ENGAGE/DISENGAGE or SPREAD/FOLD ENGAGE/DISENGAGE or SPREAD/FOLD is illuminated and flashes red by signal from Operations Request Panel or Rast Control Console. Lights glow steady red when YES or NO pushbutton is depressed. It is extinguished when the OPERATIONS REQUEST selector (figure 2-45) is turned.
Figure 2-46.- FDSSS Bridge/ClC Response Panel - Controls and Indicators (Sheet 2).
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ITEM NO.
NOMENCLATURE FUNCTION 3 Switch, Pushbutton· YES Switch transmits a YES response to Operations Request Panel or Rast Control Console. Switch is illuminated blue when system is energized and illuminated green when depressed. When OPERATIONS REQUEST selector (figure 2-45) is turned. 4 Indicator· BIFR or VERTREP HIFR or VERTREP is illuminated and flashes red by a signal from Operations Request Panel or Rast Control Console. Lights glow steady red when YES or NO pushbutton is depressed. It is extinguished when the OPERATIONS REQUEST selector (figure 2-45) is turned. 5 Indicator· TRAVERSE TRAVERSE is illuminated and flashes red by a signal from Operations Request Panel or Rast Control Console. Lights glow steady red when YES or NO pushbutton is depressed. It is extinguished when the OPERATIONS REQUEST selector (figure 2-45) is turned. 6 Switch, Pushbutton· NO Switch transmit a NO response to Operations Request Panel or Rast Control Console. Switch is illuminated blue when system is energized and illuminated red when depressed. When OPERATIONS REQUEST selector (figure 2-45) is turned, the red light is extinguished and the switch illuminates blue. 7 Buzzer Sounds when a signal is received from Operations Request Panel or Rast Control Console. 8 Switch, Pushbutton - BUZZER ON or BUZZER OFF Buzzer is placed in BUZZER ON (ready) condition by depressing switch. Switch illuminates amber when set in BUZZER ON or OFF position. Buzzer is de-energized by depressing the YES or NO pushbutton (Items 3 or 6). 9 Indicator - RED DK STATUS Energized by RED OK STATUS switch on Operations Request Panel or Rast Control Console. Illuminates red when energized. It is extinguished when de-energized.
Figure 2-46.- FDSSS Bridge/ClC Response Panel - Controls and Indicators (Sheet 2).
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ITEM NO.
NOMENCLATURE FUNCTION 10 Indicator - AMBER DK STATUS Energized by AMBER OK STATUS switch on Operations Request Panel or Rast Control Console. Illuminates amber when energized. It is extinguished when de-energized. 11 Indicator - GREEN DK STATUS Energized by GREEN DK STATUS switch on Operations Request Panel or Rast Control Console. Illuminates green when energized. It is extinguished when de-energized. 12 Potentiometer - Switch Illumination Controls intensity of switch/indicator lights. 13 Fuse Fl, 1 amp. 14 Indicator WAVE-OFF Illuminated blue when system power is ON. When Wave-off is initiated, indicator indicates a flashing red display. Switch illumination returns to blue, when wave-off is de-energized.
Figure 2-46.- FDSSS Bridge/ClC Response Panel - Controls and Indicators (Sheet 3).
Figure 2-47.- RAST Station Control Console - Control Indicators (Sheet 1 of 2). 2-73 UNCLASSIFIED
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Figure 2-47.- RAST Station Control Console - Control Indicators (Sheet 2 of 2).
2.4.8 FDSSS and RAST System Operation The procedures required to bring the FDSSS from OFF to STANDBY and then to full operational condition are defined in the following paragraphs. The RAST System procedures are also included.
WARNING
Voltages which are dangerous to life are present in the FDSSS and RAST Systems. Prior to energizing the systems, ensure all covers and panels are securely in place.
INITIAL CONTROL SETTINGS Prior to energizing the FDSSS and RAST Systems, ensure controls are positioned in accordance with table 2-6.
NOTE
Ship's emergency power supply must be energized and input voltage (115 vac) available at the FDSSS operations request panel and at the RAST control console.
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ASSEMBLY CONTROL FIGURE NO. ITEM NO. POSITION FDSSS Operations Request Panel OPERATIONS REQUEST function selector (rotary) switch 3 4 OFF PANEL ILLUM. potentiometer 3 9 Full clockwise (maximum intensity) DK STATUS INTENSITY 3 13 50 percent intensity position FDSSS Bridge/CIC Response Panel Switch/indicator illumination potentiometer 4 12 Full clockwise (maximum intensity) RAST Machinery Space RAST Power ON/OFF switch "OFF" position Test Control Panel local remote switch Set to remote position RAST Station Control Console Panel illumination potentiometer 5 2 50 percent intensity position
Table 2-6.- FDSSS and RAST Systems -Initial Control Settings.
2.4.9 Turn-on Procedures To energize the FDSSS and RAST Systems, proceed according to the procedure provided in table 2-7. At completion the systems are in standby and ready for operation.
2.4.10 System Turn-off When helicopter operations are complete, turnoff the Wave-off Light FDSSS and RAST Systems as follows:
a. Remove Wave-off Light System from the flash mode by pressing the wave-off switch at the location of wave-off initiation.
NOTE The switch which initiated wave-off will be indicated by the respective indicator on the Master Control Panel.
b. Set SYSTEM CIRCUIT BREAKER (CB- 1) on Master Control Panel (GIOOA) to OFF.
c. De-energize FDSSS Operations Request Panel by depressing SYSTEM POWER ON switch; panel lights will extinguish.
d. Set local/remote switch located in the RAST machinery space on the winch hydraulic unit to remote. 2-75 UNCLASSIFIED
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e. Set RAST Power ON/OFF switch to OFF. (Switch located in RAST machinery space.)
Table 2-7.- FDSSS and RAST Systems –Turn-on Procedures. 2-76 UNCLASSIFIED
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2.5.0 WAVE-OFF/CUT SYSTEM This section contains information describing each assembly of the Mk 2 Mod 1 Wave- off/Cut System (Figure 2-48). Information is also provided which will enable operating personnel to prepare and operate the Wave-off/Cut System. The information provided in this section is presented under the following topics:
1. Purpose of Wave-off/Cut System. 2. Physical description. 3. Operating instructions.
Figure 2-48.- Wave-off/Cut System. 2-77 UNCLASSIFIED
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2.5.1 Purpose of Wave-Off/Cut System The Wave-off/Cut System is an electronic system designed for use on LPH-2, LPH-4, LHA-1, LHD-1, LPD-1 and LPD-4 class ships in conjunction with an optical landing aid providing glide path information. When the wave-off lights are flashing, it is an indication to the pilot that he is to abort the landing and initiate a new landing approach. The cut lights are used as signal lights to communicate specific messages to the pilot in the event of radio communication loss. A wave-off/cut light assembly is mounted on each side of the appropriate optical landing aid providing glide path information. The light assemblies are located in accordance with the ships installation guidance drawing.
2.5.2 Physical Description A detailed description of the Wave-off/Cut System is provided. The assemblies that comprise the system together with their unit numbers are as follows:
1. Master control panel assembly (L100)
2. Remote panel assembly (L200, L200A)
3. Junction box assembly (L400)
4. Wave-off/cut light assembly (L500, L500A)
5. Portable switch assembly (L600)
NOTE
L600 not required for LPD class after incorporation of ACS SGSI and WOLS S/C 33, Rev A, unless used with master control panel.
2.5.3 Technical Characteristics The technical characteristics of the Wave-off/Cut System are listed in Table 2-8.
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MODE CHARACTERISTICS Light Intensity
Flash Rate - Wave-off
Wave-off/Cut Initiation
Wave-off/Cut Monitor Adjustable from a variable minimum brightness to 100%.
Variable rate at 50% duty cycle. Preset at 90 flashes/min.
Activated from any one of four positions with command location indication on the master control panel.
A "positive" indicator, sensing voltage to the lamps; flashes when the wave-off lights are operating. Indicates when cut lights operate.
Table 2-8.- Technical Characteristics.
INPUT POWER REQUIREMENTS The power required to operate the Wave-off/Cut System is supplied from the ship’s emergency power supply. The voltage and frequency of the 115-volt, 60Hz, 15 ampere source (ungrounded) must be regulated to within 10 percent.
MASTER CONTROL PANEL (L100) The master control panel (Figure 2-49) is signal processing, distribution and control center for the Wave-off/Cut System. Sheet 2 of Figure 2-49 describes the function of the controls and indicators on the master control panel.
Removal of the panel face plate provides access to the card cage assembly, which holds the monitor, flasher/driver and extender cards, the step-down transformer and the terminal boards used for system interconnection wire terminations.
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Figure 2-49.- Master Control Panel (L100) - Controls and Indicators (Sheet 1 of 2).
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Figure 2-49.- Master Control Panel (L100) - Controls and Indicators (Sheet 2 of 2).
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REMOTE PANEL ASSEMBLY (L200, L200A) There are two remote panels (Figure 2-48 item 2) used in the Wave-off/Cut System. The panels are identical. Figure 2-51 describes the function of the remote panel controls and indicators.
Removal of the panel face plate provides access to the dimmer board assemblies and the terminal board used for system interconnection.
Figure 2-50.- Remote Panel (L200 and L200A) - Controls and Indicators. 2-82 UNCLASSIFIED
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JUNCTION BOX ASSEMBLY (L400) Junction box assembly L-400 (Figure 2-48) is a moisture and dust proof unit which provides the means for connecting the cable from the master control panel to the wave-off/cut light cables. It is located within ten feet of the wave-off/ cut light assemblies.
WAVE-OFF/CUT LIGHT ASSEMBLY (L500, L500A) The wave-off/cut light assemblies (Figure 2-48) are identical units, which are installed one on each side of the stabilized platform. System interconnecting cabling connects by way of a connector located at the rear of each lamp housing. This connector has a cover, attached, with a retaining chain, which is used to prevent moisture and dirt from entering the connector when the interconnecting cable is not attached.
NOTE Portable switch is not required for LPD class after incorporation of ACS SGSI and WOLS S/C 33, Rev A, unless used with master control panel.
PORTABLE SWITCH ASSEMBLY (L600) The portable switch (Figure 2-51) is a hand-held unit which can be connected directly to the master control panel (L100). Figure 2-51 describes the function of the switches on the portable switch assembly.
2.5.4 Operating Instructions Information is provided for operating the Wave-off/Cut System in normal and remote operational mode. This information is presented under the following topics:
1. System controls, indicators, and fuses 2. Safety precautions 3. System initial control settings 4. System turn-on procedure 5. System normal and remote operation modes 6. System turnoff procedure
SYSTEM CONTROLS AND INDICATORS The information necessary to familiarize personnel with the operating controls, indicators, and fuses is presented in Figures 2-49, 2-50, and 2-51. The information provided in these figures will enable personnel to locate, identify, and understand the function of each component listed.
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Figure 2-51.- Portable Switch (L600) - Controls.
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2.5.5 Safety Precautions The safety precautions given in the following warning are to be strictly adhered to by all personnel coming in contact with the Wave-off/Cut System.
WARNING Voltages which are dangerous to life are used in the Wave-off/Cut System. Before applying power to the Wave-off/Cut System, all covers and panels must be secured.
2.5.6 System Initial Control Settings Information concerning the proper initial control settings and the preferred order in which to make these settings is provided in Table 2-9.
ASSEMBLY CONTROL POSITION Master Control Panel (L100)
Remote Panel (L200 and L200A) SYSTEM CIRCUIT BREAKER REMOTE OVERRIDE SWITCH CUT INTENSITY PANEL ILLUMINATION WAVE-OFF INTENSITY
INTENSITY OFF Normal, Toggle down Set at 50% Full CW (max intensity) Set at 50%
Full CW (max intensity)
Table 2-9.- System Initial Controls Settings.
2.5.7 System Turn-on Procedure The system turn-on procedure, which is performed after the controls are initially set, is accomplished by following the steps as outlined in Table 2-10.
2.5.8 System Normal and Remote Operating Modes At the completion of the turn-on procedure, as described in Table 2-10, the Wave-off/ Cut System is in the normal mode of operation. In the normal mode of operation, wave- off or cut signals may be initiated from any one of four locations. They are: master control panel, remote panels (L200 and L200A) and portable switch.
The remote override mode of operation is used when wave-off initiation from a remote location is to be prevented or overridden. To place the system in the remote (override) mode of operation, raise the switch guard on the REMOTE OVERRIDE SWITCH (2, Figure 2-49) and place switch in the "UP" (override) position.
The remote panel wave-off and cut switches and the portable switch are now out of the circuit; however, wave-off or cut signals may still be initiated from the master control panel.
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To remove the system from the remote override mode and enable remote operation, press REMOTE OVERRIDE SWITCH down and lower the switch guard.
Table 2-10.- System Turn-on Procedure.
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2.5.9 System Turnoff Procedure When helicopter operations are complete, refer to the following for proper Wave-off/Cut System turnoff procedures.
1. Remove wave-off system from the flash mode by pressing the wave-off switch that originally initiated the wave-off.
NOTE The switch which initiated the wave-off will be indicated by its respective indicator on the master panel.
2. Place the SYSTEM CIRCUIT BREAKER on the master control panel in the "OFF" position.
2.5.10 Theory of Operation This section discusses the theory of operation of the Wave-off/Cut System. It includes diagrams of the various components to aid in the understanding of the text.
WAVE-OFF/CUT CIRCUITS A block diagram of the Wave-off/Cut System is shown in Figure 2-52. The master control panel (L100) is located in the pri-fly flight control station along with the pri-fly remote panel (L200A). Wave-off and cut lamps (L500 and L500A) are located on either side of the stabilized glide slope indicator (SGSI). Platform junction box (L400) is located within 10 feet of the wave-off/cut lights. The bridge remote panel (L200) is located on the bridge nearest the most used approach side of the ship. The deck station portable switch junction box (L300) is located at the lighting control station near the flight deck access hatch.
All of the system circuits except for the remote panel dimmers are located in the master control panel. In order to understand system operation, the functioning of the master control panel must be thoroughly understood. In the Master Control Panel there are two circuit cards common to the wave-off and cut systems; the monitor card and the flasher/driver card. The names of these cards are descriptive of their functions.
When the system circuit breaker, which doubles as an on-off switch, is turned on, power is supplied to the system. 115-vac power is supplied to transformer T1 and to the wave- off lamps through the Silicon Controlled Rectifiers (SCR). The SCRs are not gated on unless a wave-off or cut command is given.
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Figure 2-52.- Wave-Off/Cut System Block Diagram. 2-88 UNCLASSIFIED
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The output of transformer T1 goes to the monitor and flasher driver circuit cards and to the system lamps and switches. Diodes CR1 and CR2 make up a full wave rectifier circuit and supply DC power to everything but the circuit cards.
The wave-off flasher/driver card receives its input command from the wave-off monitor card and provides variable intensity, a first full brightness flash, continuous flashing, and drive signals for the two SCR’s. The SCR’s continue to be gated and wave-off lights flash as long as the wave-off switch remains in the actuated condition. (Refer to Figure 2- 49, Item 8.)
The wave-off monitor card receives all the wave-off commands from the various wave- off switches and drives lamps to indicate which switch was pushed. It also drives the panel dimmer, provides a wave-off output to the flasher/driver card, senses voltage across the wave-off lamps, and provides a positive indication of a wave-off at each panel.
The cut flasher/driver card receives its input command from the cut monitor card and provides a continuous drive signal for the two SCR’s as long as the cut switch is actuated. Variable intensity is for the cut lamps.
The cut monitor card receives all cut commands from the several cut switches and drives lamps to indicate which switch was pushed. It also drives the panel dimmer, provides a cut output to the flasher/driver card, senses voltage across the cut lamps and provides a positive indication of a cut command at each panel.
SILICON-CONTROLLED RECTIFIERS (SCR'S)
A silicon-controlled rectifier (SCR) is a special diode (see Figure 2-53). Normally it will not pass current in either direction; however, if a positive voltage is applied between its gate and cathode it will turn on and pass current in one direction. Once turned on, an SCR will remain on until the anode-cathode voltage drops to zero or reverses.
In the wave-off system the SCR's are connected in inverse parallel configuration. This means they are connected cathode-to-anode. In this way, each diode will pass one half cycle of the sixty-cycle line.
An SCR can be checked out of circuit by using a multimeter. This is done by setting the multimeter on its high-ohms scale and measuring the resistance between anode and cathode in both directions. The meter should indicate open. To check the gate circuit, connect the positive meter lead to the anode and the negative to the cathode with the meter set at its XIO scale. The meter should indicate an open. With the leads still attached, connect the gate to the anode. The meter should indicate some value of resistance. These are crude tests and mayor may not work on all units. An in-circuit test is the best test. 2-89 UNCLASSIFIED
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Figure 2-53.- Silicon-Controlled Rectifier (SCR).
2.6.0 VERTICAL/SHORT TAKE-OFF AND LANDING OPTICAL LANDING AID SYSTEM HOVER POSITION INDICATOR (HPI) This section provides a brief description and principles of operations for the Hover Position Indicator (HPI).
The HPI with the wave-off/cut system make up the Vertical/Short Takeoff and Landing Optical Landing Aid System (VSTOL OLA). VSTOL OLA was designed in support of vertical/short takeoff aircraft, such as the AV8. By use of the Vertical/Short Takeoff and Landing Optical Landing System (VSTOL OLS), an AV8 pilot can visually establish and maintain the proper glide slope for a safe approach to the ship. Then, prior to crossing the ramp, the HPI is utilized for the final phase of the approach.
2.6.1 Principles of Operation
HPI SYSTEM The HPI system is mounted on the aft end of the island. The HPI System (figure 2-54) consists of a vertical group of five lights and a horizontal group of three lights with a single red light mounted nine feet in front of the display. The unit is designed to place the pilot’s eye 49 feet above the deck when the red light is placed at the intersection of the vertical and horizontal groups of lights.
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Figure 2-54.- HPI System.
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PILOT USE OF VSTOL OLA The VSTOL OLS provides the approaching AV8 pilot with glide path information from approximately one (1) nautical mile to the hover transition point. The pilot transitions to hover approximately one mile from the ship and continues to fly the VSTOL OLS up to 50 ft from the ship, where the pilot will refer to visual cues on the ship and the HPI. The pilot lines up on the ship’s lighted centerline and flies forward until the HPI red indicator light is centered in the display as shown in figure 2-55. When this occurs, the pilot is over the touchdown zone with his eyes approximately 49 feet over the deck. As the pilot vertically descends to a touchdown, the HPI gives him a relative idea of his rate of closure with the deck as the red light orientation changes in its apparent alignment with the vertical amber HPI lights. If during any part of the recovery evolution an unsafe landing condition develops, a red flashing wave-off will be given utilizing the Wave-Off/Cut System. The green cut lights flash to the pilot if he is too low in approach. An alternate wave-off and cut light actuation is a signal to the pilot to “bingo” or to go to an alternate landing site.
Figure 2-55.- HPI Display Indicator Interpretation.
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2.6.2 HPI System Description The HPI, see figure 2-56 for block diagram, consists of 3 major assemblies and is mounted on the aft end of the ship’s island near the wave-off/cut lights.
a. Control Panel Assembly (M100).
b. Junction Box Assembly (M200).
c. HPI Light Assembly (M300).
Figure 2-56.- HPI System Block Diagram.
CONTROL PANEL ASSEMBLY (M100) The control panel assembly (figure 2-57) is mounted in the Primary Flight (Pri-Fly) control. The assembly is used to control the on- off operation of the HPI system and contains 4 variacs, which are used to adjust the intensity of the lamps that are mounted on the HPI light assembly. The front panel of the assembly contains an indicator and all of the controls, which are used to operate the HPI system. The indicator is Night Vision Device (NVD) compatible. The front panel is hinged and, when open, permits access to all interior components for maintenance. Figure 2-58 illustrates the front panel controls and indicators. Their functions are described in table 2-11. Two stuffing tubes are provided in the bottom of the assembly for cable entrance.
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Figure 2-57.- Control Panel Assembly (M100).
Figure 2-58.- HPI Control Panel Assembly Controls and Indicators.
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ITEM NO. NOMENCLATURE/DEVICE FUNCTION 1 WHITE LIGHT INTENSITY Control Adjust intensity of white lights on HPI light assembly. 2 GREEN LIGHT INTENSITY Control Adjust intensity of green lights on HPI light assembly. 3 AMBER LIGHT INTENSITY Control Adjust intensity of amber lights on HPI light assembly. 4 RED LIGHT INTENSITY Control Adjust intensity of red lights on HPI light assembly. 5 System ON-OFF Toggle Switch Applies 115 VAC, 60 Hz power to HPI system. 6 System ON Indicator Indicates that power has been applied To HPI system.
Table 2-11.- Control Panel Assembly Controls and Indicators.
JUNCTION BOX ASSEMBLY (M200) The Junction Box Assembly (figure 2-59) is mounted just below the HPI light assembly. The assembly is used to interconnect the control panel assembly and the HPI light assembly.
Cables enter the assembly by means of 10 stuffing tubes, which are installed in the sides of the box. Access to the interior terminal board is gained by loosing the 10 captive screws, which secure the top of the box assembly.
HPI LIGHT ASSEMBLY (M300) The HPI Light Assembly (figure 2-60) consist of a vertical group of 5 light fixture assemblies and a horizontal group of four (4) light fixture assemblies with a single red lamp mounted 9 feet in front of the display. In the vertical group, the two top light fixtures have clear globes and the two lower light fixtures have amber globes. The center light fixture is part of the horizontal group.
The horizontal group fixtures have green globes. Lamp is a 115 VAC, 50-watt rough service lamp whose brightness is remotely adjustable from 0-100 percent. The fixtures are supported by a tubular structure and are stiffened by support struts.
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Figure 2-59.- Junction Box Assembly (M200).
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Figure 2-60.- HPI Light Assembly (M300).
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2.7.0 VERTICAL AND SHORT TAKE-OFF AND LANDING OPTICAL LANDING SYSTEM (VSTOL OLS) This section provides organizational level operation and maintenance information for VSTOL OLS. The information includes equipment description and principles of operation.
2.7.1 Equipment Description The VSTOL OLS is a visual landing aid that displays a glideslope path for aircraft approaching a flight deck. The VSTOL OLS guides the aircraft during the landing approach to a position 50 feet above the flight deck for transition to the hover position indicator (HPI). Electronic circuitry compensates for the ship’s yaw and pitch to ensure correct glideslope path. Operational controls are located on the remote control assembly located in the primary flight control station (Pri-Fly). The VSTOL OLS consists of 14 units and accommodates both LHA and LHD ships.
2.7.2 Purpose The VSTOL OLS is a visual landing aid that displays glidepath and trend information to a VSTOL pilot approaching the flight deck. The system presents a display that is visible at a range of 0.8 nm and at a ceiling of 200 feet. The VSTOL OLS guides the aircraft during landing approach to a position 50 feet above the flight deck, where the pilot transitions to the hover position indicator (HPI) system, for hover stop and vertical descent information during the final phase of approach.
2.7.3 System Description The VSTOL OLS display (figures 2-61 and 2-62) consists of lower and upper indicator box assemblies units 11 and 12 mounted vertically between horizontal port side (LHA)/port side (LHD) and starboard side datum arm assemblies units 13 and 14. The system displays an optimal glidepath to the pilot that is compensated for ship's pitch and roll by internal electromechanically stabilized optics. The glidepath basic angle is adjustable from 2.00 to 4.00 o in 0.25o increments. With a basic angle of 3o selected, the system can compensate for a maximum roll of ±14o or a maximum pitch of ±3o. At basic angles other than 3o, the system can compensate for a maximum roll of ±12o or a maximum pitch of ±2.25o. The system displays a virtual image (ball) that is dynamically stabilized to compensate for ship's pitch and roll motion. The ball appears aligned between two horizontal datum arm assemblies (figure 2-63) when the pilot is approaching on the optimum glidepath. As the aircraft transitions about the optimum glidepath, the ball will appear to be above or below the datum arm lights if the pilot is approaching high or low relative to the optimum glidepath.
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Figure 2-61.- Elevation View of VSTOL OLS.
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Figure 2-62.- Top View of VSTOL OLS.
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Figure 2-63.- VSTOL OLS Optical Presentation.
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If the pilot's approach is above the optimum glidepath by greater than 1o, the display presents a flashing amber ball. If the approach is below the optimum glidepath by greater than 0.8o, the display presents a constant red ball. If the approach is greater than 1o below the optimum glidepath, the display presents a flashing red ball. Refer to figures 2-64 and 2-65 for system operational characteristics.
Figure 2-64.- VSTOL OLS Vertical Coverage.
Figure 2-65.- VSTOL OLS Azimuthal Coverage.
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2.7.4 Major Components Description and Principles of Operation The VSTOL OLS consists of 14 major components (units). The following paragraphs provide descriptions, typical physical locations (figure 2-66), and principles of operation for each unit.
Figure 2-66.- VSTOL OLS Block Diagram Example.
POWER CONTROL ENCLOSURE ASSEMBLY Unit 1 controls system power distribution and is typically located adjacent to primary flight control station (Pri-Fly). It contains EMI filtering, 28 Vdc system power supplies, system power control relays, a transient suppression circuit, and circuit-breaker protection for system components and subassemblies.
ELECTRONICS ENCLOSURE ASSEMBLY Unit 2 is located adjacent to Pri-Fly and is the signal processing, distribution, and control center for the VSTOL OLS. It consists of a BITE panel assembly for system testing and troubleshooting, circuit breaker panel assembly, 400 Hz inverter for units 11 and 12 synchros, EMI filter, and card cage assembly containing PWAs for the CPU and CPU supporting circuits, variac interface, stabilized optics table (SOT) status interface, synchro-to-digital (S/D) converters, and stepper motor driver circuitry.
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VARIAC ASSEMBLY Unit 3 is typically located adjacent to Pri-Fly and contains the transformer that controls the brightness of source lights in units 11 and 12 through a computer controlled relay in unit 1.
VARIAC ASSEMBLY Unit 4 is typically located adjacent to Pri-Fly and contains the motor driven transformer that controls the brightness of the unit 13 datum lights through a computer-controlled relay in unit 1.
VARIAC ASSEMBLY UNIT 5 is typically located adjacent to Pri-Fly and contains the motor driven transformer that controls the brightness of the unit 14 datum lights through a computer-controlled relay in unit 1.
REMOTE CONTROL ASSEMBLY Unit 6 contains controls for power on/off and source/datum light intensity. It houses various indicators including system performance lights, lamp out/cell out indicators, stabilization status lights, and troubleshooting status lights. A dimmer controls the intensity of the panel illumination lights.
LIGHTING JUNCTION BOX ASSEMBLY Unit 7 is typically located on the aft portion of the island superstructure and is the wiring interface between system display lighting components in units 1, 9, 10, 11, 12, 13, and 14.
STABILIZATION JUNCTION BOX ASSEMBLY Unit 8 is typically located on the aft portion of the island superstructure and is the wiring interface between the system stabilization circuit components in units 2, 11, and 12.
LOWER SOURCE LIGHT TRANSFORMER ASSEMBLY Unit 9 is typically located on the aft portion of the island superstructure and contains two step-down transformers that convert motor-driven transformer voltages to lamp drive voltages to power the lamps in unit 11.
UPPER SOURCE LIGHT TRANSFORMER ASSEMBLY Unit 10 is typically located on the aft portion of the island superstructure and contains two step-down transformers that convert motor-driven transformer voltages to lamp drive voltages to power the lamps in unit 12.
LOWER INDICATOR BOX ASSEMBLY Unit 11 is a sealed metal structure attached to a mounting tower located aft of the island superstructure. It contains 10 SOTs, 10 lenses, 2 motor drive assemblies, source light failure interface circuitry, and supporting hardware. Eight light cells have amber lens filters and two light cells have red lens filters.
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UPPER INDICATOR BOX ASSEMBLY Unit 12 is a sealed metal structure attached to a mounting tower located aft of the island superstructure. It is essentially identical to unit 11, except that the SOT assembly with the flashing solenoid is located in position 10 and all 10 light cells have amber lens filters.
PORT SIDE (LHA)/PORT SIDE (LHD) DATUM ARM ASSEMBLY Unit 13 is located on the aft portion of the island superstructure and in combination with unit 14 provides a horizontal reference to units 11 and 12. Unit 13 consists of four equally spaced lamp fixtures fitted with 120 Vac, 300 W medium floodlights.
STARBOARD SIDE DATUM ARM ASSEMBLY Unit 14 is located on the aft portion of the island superstructure. It is mounted on the opposite side of units 11 and 12 from unit 13. The operation of unit 14 is identical to that of unit 13.
2.7.5 System Functional Signal Flow The following paragraphs describe the major VSTOL OLS signals shown on figure 2-67.
Figure 2-67.- VSTOL OLS System Functional Block Diagram Example.
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Wiper Vac Wiper voltages from units 3, 4, and 5 are routed via units 1 and 7 to units 9, 10, 13, and 14 to set intensity of lower source lights, upper source lights, inboard datum lights, and outboard datum lights, respectively. Wiper Vac voltages range from 0 to 115 Vac signals that determine intensity of datum and source lights. The transformer wiper voltages are also supplied via unit 1 to unit 2, where they are converted to dc signals that are monitored by CPU PWA A1A5.
12/24 Vac AC voltages output from units 9 and 10 transformers that determine intensity of units 11 and 12 source lights. Zero to 12 Vac (from transformer center taps) is supplied for normal coverage cells, and 0 to 24 Vac is supplied for extended coverage cells. Levels of these voltages are dependent on unit 3 wiper 0-115 Vac input to units 9 and 10.
115 Vac/28 Vdc These voltages are supplied from unit 1 through unit 7 to units 11 and 12. The 115 Vac is used for heater gaskets and fans. The 28 Vdc is used by 15 Vdc regulator assembly 11/12A12A2 and parallel-to-serial converter PWA 11/12A12A1 inhibit circuit. The voltages are also supplied to unit 2 for use by various PWAs, 5 Vdc power supply PS1 (115 Vac), and 400 Hz inverter PS2 (28 Vdc).
5 Vdc BIT Signals transmitted from unit 6, via unit 1, to unit 2 CPU PWA A1A5, so that CPU PWA A1A5 can monitor output of unit 6 DC/DC converter PS1 and voltage regulator A1A1U1.
28 Vdc Voltage supplied to unit 6 from unit 1 for use by standby indicator light on system control module assembly A4, and DC/DC converter PS1 for generation of unit 6 logic voltage.
Power Relay Control Signal applies ground to coil of unit 1 main power control relay K1 when System Power switch in unit 6 is pressed, or when System Power switch in unit 2 is set to ON.
15 Vdc BIT BIT signal transmitted from units 11 and 12 to unit 2 via unit 8. Provides 15 Vdc (logic voltage) regulator status to unit 2 CPU PWA A1A5.
Motor F/B 400 Hz ac voltages from drive assembly synchros located in units 11 and 12. Signals provided via unit 8 to unit 2 CPU PWA A1A5 and stepper motor feedback S/D converter A1A2.
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115 Vac (Phase A, B, C) Three phase, 60 Hz, MIL-STD-1399 compatible ship's power, provided to unit 1 terminal board TB1 for distribution and voltage reduction.
Relay Control Signals from unit 2 CPU PWA A1A5 that apply and remove grounds (via unit 2 variac interface PWA A1A1) at low side of unit 1 relay K2, (inboard datum lights) relay K3, and (outboard datum lights) relay K4 coils. Application of ground to low side of relay coil causes related lamps to illuminate.
28 Vdc - Motors DC voltages supplied from unit 1 silicon rectifiers CR1 thru CR4 to activate unit 2 driver PWAs A1A13 thru A1A16 (lower) and A1A18 thru A1A21 (upper).
115 Vac Variac Power Two phases of 115 Vac from unit 1 that are supplied to units 3, 4, and 5 when related unit 1 relay K2, K3, and K4 are energized.
Stepper Mtr Inputs Signals generated by unit 2 driver PWAs A1A13 thru A1A16 (lower), and A1A18 thru A1A21 (upper) that determine the step indexing/position of each stepper motor. Each stepper motor has four connections which can energize either one or two phases of each motor.
Ref, 2X Roll, 36X Roll, 36X Pitch 400 Hz signals via unit 2 ship gyro S/D converter A1A3, to unit 2 CPU PWA A1A5 that are used to determine correct position for each of the drive shafts located in units 11 and 12.
Otbd/Inbd Datum Intensity Control Signals from unit 2 CPU PWA A1A5 to units 4 and 5 control sections. Allows unit 2 CPU PWA A1A5 to increase or decrease variac intensity via variac interface PWA A1A1.
Source Intensity Control Signal from unit 2 CPU PWA A1A5 to unit 3 control section. Allows unit 2 CPU PWA A1A5 to increase or decrease variac intensity via variac interface PWA A1A1.
Failure Ind BIT status information for various system components. Information is transferred between units 2 and 6 (e.g., switch parity information from unit 6 to unit 2, and lamp out/cell out information from unit 2 to unit 6).
Switch Settings Signals provide unit 6 Basic Angle switch, Source Intensity switch, and Datum Intensity switch setting information to unit 2. Basic angle settings range from 2.00 to 4.000 in 0.250increments. Source and datum intensities range from 0 to 10 in increments of 1.
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2.7.6 Light Intensity Control Source light and datum light intensities are set at unit 6 then processed by unit 2 CPU PWA A1A15.
Source light intensity information (figure 2-68) from unit 6 is routed through unit 2 to unit 3 where the correct voltage is generated and routed through unit 1 to unit 7 and then to units 9 and 10. Units 9 and 10 convert the motor-driven transformer voltages to lamp drive voltages that are routed to the lamps in units 11 and 12.
Figure 2-68.- Source Light Intensity Control Block Diagram.
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Datum intensity information (figure 2-69) from unit 6 is routed through unit 2 to units 4 and 5 where the voltage for the corresponding brightness is generated and routed through units 1 and 7 to lamps in units 13 and 14.
Figure 2-69.- Datum Light Intensity Control Block Diagram.
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2.7.7 Display Stabilization The optimal glidepath angle (2 to 40) is set at unit 6. Unit 2 receives gyro pitch and roll information (figure 2-70), and SOT assembly 11/12A1 thru 11/12A10 status information from units 11 and 12 synchros. Unit 2 CPU PWA A1A5 then compares the gyro information to the current position of the SOT assemblies 11/12A1 thru 11/12A10 and outputs the appropriate signals to units 11 and 12 stepper motors to move the SOT assemblies 11/12A1 thru 11/12A10 to present the display selected at unit 6.
Figure 2-70.- VSTOL OLS Simplified Stabilization Block Diagram.
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The display is stabilized by moving the internal optical elements in units 11 and 12. Each SOT assembly 11/12A1 thru 11/12A10 is connected to port and starboard vertical shafts. Pitch and roll stabilization is maintained by moving the vertical shafts.
Pitch stabilization is attained by moving the port and starboard shafts up or down in unison. Since all SOT assemblies 11/12A1 thru 11/12A10 are rigidly coupled to the shafts, they all move simultaneously. The amount of shaft travel required to stabilize the display is determined by the gyro pitch input to the system.
Roll stabilization is performed in the same manner as pitch stabilization, except that the vertical shafts are moved differentially. Therefore, the system can be roll stabilized when there is no pitch motion.
2.8.0 IMPROVED FRESNEL LENS OPTICAL LANDING SYSTEM (IFLOLS) The Improved Fresnel Lens Optical Landing System (IFLOLS) Shipboard MK13 MOD 0 is a visual landing aid system that displays glide path and trend information to a fixed wing pilot approaching the flight deck. The system presents a display that is visible at a range of 1.0 nautical mile.
2.8.1 System Description The Shipboard MK13 IFLOLS deck edge display (figure 2-71) consists of an indicator display assembly (Unit 1) mounted vertically between two vertically oriented wave- off/cut displays (Units 11 and 12), which are flanked by two horizontally mounted datum arms (Units 8 and 9). The system displays an optimal glide path to the pilot that is compensated for ship's pitch, roll and heave by internal electro-mechanically Stabilized Optics Tables (SOTs).
The glide path basic angle is adjustable from 3.0° to 4.5° in 0.25° increments. The hook path command is adjustable between 50 feet and 350 feet in 5-foot increments and the aircraft select hook-to-eye setting is adjustable between 12 feet and 22 feet in 0.25-foot increments. Stabilization mode is selectable between line and inertial modes.
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Figure 2-71.- IFLOLS MK13 Mod 0 Deck Edge Equipment.
The system displays a virtual image (ball) that is dynamically stabilized to compensate for ship's pitch, roll and heave motion. The ball appears aligned between two horizontal datum arms (figure 2-72) when the pilot is approaching on the optimum glide path. As the aircraft transitions about the optimum glide path, the ball will appear to be above or below the datum arm lights if the pilot is approaching high or low relative to the optimum glide path.
If the pilot's approach is below the glide path by greater than 0.45°, the display presents a flashing red ball (figure 2-72). For all other flight profiles, the system presents a yellow ball. Refer to figure 2-73, figure 2-74 and table 2-12 for system operational characteristics.
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Figure 2-72.- IFLOLS MK13 and MK14 Optical Presentation.
Figure 2-73.- IFLOLS MK13 Vertical Coverage. 2-113 UNCLASSIFIED
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Figure 2-74.- IFLOLS MK13 Azimuth Coverage.
Table 2-12.- IFLOLS MK13 Operational Characteristics.
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2.8.2 System Equipment Groups The system equipment groups (figure 2-75) consist of the deck edge equipment group, the control room equipment group, the Pri-Fly equipment group and the LSO equipment group.
Figure 2-75.- IFLOLS System Equipment Block Diagram Example.
DECK EDGE EQUIPMENT GROUP. The deck edge group consists of the indicator assembly (Unit 1), twelve SOTs (Unit 6) housed in Unit 1, the mounting structure (Unit 7), the datum arm assemblies (Units 8 and 9), the wave-off/cut lamp arm assemblies (Units 11 and 12), the lighting junction box (Unit 15), the transformer enclosure assembly (Unit 16) and the wave-off monitor (Unit 18).
LENS ROOM EQUIPMENT GROUP. This group consists of the lens room control panel assembly (Unit 2), the heave sensor assembly (Unit 5) and the emergency wave-off control panel (Unit 13).
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PRI-FLY EQUIPMENT GROUP. This group consists of the Pri-Fly control panel assembly (Unit 3) for IFLOLS configurations 3429AS0100-1 and -2 or Pri-Fly/cross check control panel assembly (Unit 3) for IFLOLS configuration 3429AS0100-3.
LSO EQUIPMENT GROUP. This group consists of the LSO control panel assembly (Unit 4), the distribution junction box (Unit 10) and the portable switch assembly.
2.8.3 Major Components Shipboard MK 13 Description and Principles of Operation The IFLOLS MK13 MOD 0 consists of 16 separate major components. These components include Units 1 through 18. Units 6 and 14 have been incorporated into Units 1 and 10 respectively. The following paragraphs provide descriptions, typical physical locations and principles of operation for each unit. Refer to figures 2-76 and 2-77 for IFLOLS system electrical interconnect and table 2-13 for physical characteristics of units.
Figure 2-76.- IFLOLS MK13 System Interconnect Block Diagram Example.
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Figure 2-77.- IFLOLS MK13 System Interconnect Block Diagram with Service Change #3 Example.
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Table 2-13.- Shipboard IFLOLS (MK13 MOD 0) Major Components Physical Characteristics.
The indicator display assembly mounting frame (unit 7) has only preventive maintenance impact at the organizational maintenance level; therefore, unit 7 is identified for completeness only.
INDICATOR DISPLAY ASSEMBLY, UNIT 1. The indicator display assembly is a sealed metal structure attached to a mounting frame on the deck edge platform. It has port and starboard drive systems, twelve SOTs, front and rear window assemblies, twelve lenses, a heat pump and associated thermo switches, a rear electronics channel with required circuitry and two midsection access doors, one port and one starboard.
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Stabilized Optics Table (SOT) (1A1 thru 1A12). Although an integral part of the indicator assembly, the SOT is a complex and compact repairable assembly in itself. It carries primary and backup source lamps, a lamp change mechanism, a glass masked fiber optic block, a lamp changer/driver PWA and a dichroic filter. The two bottom most SOTs, 1A11 and 1A12, are called extended cells and are focused to provide a greater coverage than the standard cells (1A1 thru 1A10). SOTs 1A1 thru 1A10 use yellow dichroic filters, while SOTs 1A11 and 1A12 utilize red dichroic filters. Maintenance is limited to removing and replacing several discrete items since the SOT is a precision aligned unit.
Each SOT assembly is attached to port and starboard drive assemblies in a manner that allows SOT assembly movement to compensate for ships’ pitch, roll and heave.
LENS ROOM ELECTRONICS ENCLOSURE ASSEMBLY, UNIT 2. The lens room electronics enclosure assembly (figure 2-78) is the electrical and electronic control center of the IFLOLS system (figure 2-76). It is comprised of eight subassemblies: a left interconnect junction box, a left slope control panel, a component shelf, a lighting control drawer, right slope control panel, a power supply drawer, a card cage drawer and a right interconnect junction box subassembly. There are two sets of filtered cooling fans. One set is located under the lighting control drawer and the other below the power supply drawer.
Figure 2-78.- Lens Room Electronics Enclosure Assembly. 2-119 UNCLASSIFIED
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Left Interconnect Junction Box Subassembly (2A1A1). The junction box (figure 2-78) contains four terminal boards that provide interconnection points for all system power and lighting functions.
Left Slope Control Panel Subassembly (2A1A2). The left slope control panel (figures 2-78 and 2-79) contains five subassemblies: three are power indicators and circuit breakers for the system/subsystems, one provides fuse protection for the transient suppression network and the fifth component is the BITE panel with LED readout and lamp indicators.
Figure 2-79.- Left Slope Control Panel Subassembly.
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Emergency Wave-Off Power Circuit Breakers and Power Indicators (2A1A2A1). The IFLOLS system utilizes power from the ship’s emergency wave-off system. This external power ensures the wave-off location data will be sent to all the external interface systems when the IFLOLS system is “OFF”. As a result, this circuit breaker should only be turned “OFF” during maintenance actions when the IFLOLS and emergency wave-off systems are not needed for flight-ops. The power indicator is lit when the breaker is activated and power is present.
Component Shelf Subassembly (2A1A3). The entire area behind the left slope control panel subassembly (figure 2-78 and 2-80) is considered part of this subassembly; however, not all components are mounted on the shelf itself. The subassembly is made up of; two variacs, a fiber optic Ethernet hub, an EMI filter two relays and six terminal boards.
Figure 2-80.- Component Shelf Assembly. Lighting Control Drawer Subassembly (2A1A4). The lighting control drawer (figures 2-78 and 2-81) consists of two power supplies, three variacs, twelve terminal boards and four PWAs. The primary purposes of the lighting control drawer are to provide power and intensity control for the lighting for all five deck edge display units, provide communication with the system main CPU and to process and display deck edge lighting display faults.
The exterior face of the lighting control drawer provides additional system status information through the use of indicator lamps, circuit breakers and fuses.
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Figure 2-81.- Lighting Control Drawer Front Panel.
Right Slope Control Panel Subassembly (2A2A1). The right slope control panel (figures 2-78 and 2-82) consists of a control panel on which are mounted three subassemblies: a flat panel display, a display control module and an intensity control module. The shroud base subassembly, which forms the base of this subassembly, provides a place on which to mount two power supplies, a fiber optic transceiver, a relay and its socket, a diode, a resistor and four terminal boards.
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Figure 2-82.- Lens Room Right Slope Subassembly.
Flat Panel Display Assembly (2A2A1A1). This assembly (figure 2-82) provides the lens room operator with seven (7) visual display/touch screens: the system MAIN screen, LIGHTING screen, STABILIZATION screen, NON-STD (standard) screen, MODE/STATUS screen, CALIBRATION screen and POLE CHECK screen. The flat panel will display all BITE error conditions in the status bar area of all screens with the exception of the calibration screen. Refer to WP 008 00, table 1 for a complete listing of BITE panel error messages.
Lens Room Main Screen Display. This screen (figure 2-83) has five major elements. The status bar, which is common to all lens room screens with the exception of the CALIBRATION and POLE CHECK screens, provides fourteen discrete data elements: Aircraft (A/C) type, Hook-to-Eye (H/E) distance, Basic Angle (BA) setting, which wire is optimal and its distance from the round down, system stabilization mode, system status, failure mode, where certain system failures will be indicated, Air Officer (A/O) interlock status, whether a Hook-to-Ramp (H/R) warning has been issued, status and frequency of the system low cell flash capability, whether wave-off has been initiated, whether cut has been initiated and whether the barricade is raised. 2-123 UNCLASSIFIED
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The main screen also provides four graphical representations: hook to ramp distance, Hook Touch Down (HTD) point, which are both static and dynamic, a barricade up or down position indication, and ship pitch (trim) and roll (list) gauges (analog and digital) in degrees. On the right side of the screen are touch screen indications of which other screen can be reached from the current screen, a brightness reset touch screen indication, a touch screen indicator/switch showing whether Pri-Fly or the lens room has system control, and the ability to take control of the system at lens room.
Figure 2-83.- Lens Room MAIN Screen Display.
Lens Room Lighting Screen Display. In addition to the information provided on the status bar, which is the same as on the MAIN screen, the LIGHTING screen (figure 2-84) allows the lens room operator to observe and control source light, low cell, datum, wave off and cut lighting intensity settings. The operator/maintainer can initiate or detect low cell flash on or off, and can initiate or detect the cut light function. On the right side of the screen are touch screen indications of which other screen can be reached from the current screen, a brightness reset touch screen indication, and a touch screen indicator/switch showing whether Pri-Fly or the lens room has system control, and the ability to take control of the system at lens room.
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Figure 2-85.- Lens Room LIGHTING Screen Display.
Lens Room Stabilization Screen Display. The lens room STABILIZATION screen (figure 2-85) display shows the status bar, which is the same as on the MAIN screen. This screen permits the operator and or maintainer to switch between line and inertial stabilization modes, select between 3.50°, 3.75°, and 4.00° basic angle, change the hook path command to the 1, 2, 3, or 4 arresting wire (4th wire not applicable for CVN-76), select the type of standard aircraft on approach from a menu, enable or disable the barricade is rigged/not rigged indication and a separate touch screen area to enable changes. On the right side of the screen are indications of which other screens can be reached from the current screen, a brightness reset touch screen indication and a touch screen indicator/switch showing whether Pri-Fly or the lens room has system control and the ability to take control of the system at lens room. To make a selection on this screen, select the ENABLE button (the text will change to Enter and the button will be highlighted) then touch the desired buttons to active (the button will highlight to indicate a successful selection) and then select the ENTER button. The changes will not be activated until the ENTER button is selected. To activate a BARRICADE button, select ENABLE, BARRICADE, A/C TYPE-H/E and then ENTER. 2-125 UNCLASSIFIED
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Lens Room Nonstandard Screen Display. The lens room NONSTANDARD screen (figure 2-86) display shows the status bar, which is the same as on the MAIN screen. This screen permits the operator/maintainer to manually change the Hook Path, the Basic Angle and the Hook-to-Eye distance, to select from two sets of nonstandard aircraft types, enable or disable the barricade is rigged/not rigged indication and a separate touch screen area to ENABLE changes. On the right side of the screen are touch screen indications of which other screens can be reached from the current screen, a bite button which allows toggling of the bite panel LED, a BRT RESET (brightness) reset touch screen indication and a touch screen indicator/switch showing whether Pri-Fly or the lens room has system control and the ability to take control of the system at the lens room. To make a selection on this screen for the NONSTANDARD AIRCRAFT TYPE block, select the ENABLE button (the text will change to ENTER and the button will be highlighted), then touch the desired button to activate (the button will highlight to indicate a successful selection) and the ENTER button. To manually enter a HTD, B/A or a H/E: select ENABLE, one of the three buttons (HTD, B/A or H/E) then use the up and down arrows to select the correct value and then hit ENTER. The changes will not be activated until the enter button is selected. To activate a BARRICADE button, select ENABLE, BARRICADE, A/C TYPE-H/E and ENTER. To save a H/E setting, select the H/E manually chose either save SET1 or save SET2 only; save the H/E setting not HTD and BA.
Figure 2-86.- Lens Room NONSTANDARD Screen Display. 2-126 UNCLASSIFIED
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Lens Room Mode/Status Screen Display. The MODE/STATUS screen display (figure 2-87) is available only at the lens room station. This is the only screen, which the operator/maintainer can use to access the system CALIBRATION and POLE CHECK screens. The MODE/STATUS screen display shows the status bar, which is the same as on the MAIN screen, pitch and roll information, and the ability to select mode (ACTIVE, MOVLAS, OR CALIB), heave source (used when system set to inertial mode) and gyro source. This screen provides graphical representations of lens pitch and roll with an accompanying digital read out and a lighting status display, which graphically identifies the failure of any lamps in the deck edge display. It contains a separate touch screen area to ENABLE changes. On the right side of the screen are touch screen indications of which other screens can be reached from the current screen (this is the only screen which allows access to the CALIBRATION screen), a brightness reset touch screen indication and a touch screen indicator/switch showing whether Pri-Fly or the lens room has system control and the ability to take control of the system at the lens room.
Figure 2-87.- Lens Room MODE/STATUS Screen Display.
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Lens Room Calibration Screen Display. The CALIB RATION screen (figure 2-88) has an area, which permits the operator/maintainer to perform system static (with the drive system off) or dynamic (with the drive system on) stabilization tests by manually setting pitch, roll and heave. There is a window which shows the software program input variables, which are loaded prior to system installation and are specific for ship type and are therefore not accessible to the operator or maintainer. There is a separate touch screen area to ENABLE changes and tests and on the right side of the screen is a single touch screen indication, which permits returning to the MODE/STATUS screen (when system is in CALIBRATION mode, a POLE CHECK screen select button will also appear).
Figure 2-88.- Lens Room CALIBRATION Screen Display.
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The LIGHTING PWR area provides capabilities for turning source lights or datum lights on during any condition where a critical failure automatically turns the lights off. The source lights can be turned on by selecting ENABLE, Source ON/OFF, ENTER. The Source OFF button will change to Source ON. The datum lights can be turned on by selecting ENABLE, Datum ON/OFF and Enter. The Datum OFF button will change to Datum ON.
The BITE DISPLAY area provides capabilities for displaying various information on the BITE panel. The DISPLY FdBack Button is the default setting (i.e., feedback information will be displayed on BITE panel unless changed). To change setting, select ENABLE, DISPLY FdBack, ENTER. The next setting will be displayed (it is possible to toggle through all display settings), toggle to the desired setting and select ENTER. Refer to table 2-14 for DISPLY button description, purpose and displayed information.
Table 2-14.- BITE Display Button Feedback Functions.
The STABILIZATION TEST area provides capabilities for slewing the drive system either statically or dynamically. Select ENABLE, then select the desired tests and ENTER.
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Lens Room Pole Check Screen Display. The POLE CHECK display screen (figure 2- 89) is accessible from the CALIBRATION screen only. It provides the capability to arrow up or down to various configurations (see IFLOLS Maintenance Requirement Cards (MRCs) in order to check the system using preset parameters.
Figure 2-89.- Lens Room POLE CHECK Screen Display.
Card Cage Drawer Subassembly (2A2A2). The card cage drawer (figures 2-78 and 2- 90 consists of a card cage assembly with twenty PWA card slots, containing a total of eleven PWAs and a step mount assembly with twenty-four terminal boards.
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Figure 2-90.- Card Cage Drawer Assembly.
Power Supply Drawer Subassembly (2A2A3). The power supply drawer (figures 2-78 and 2-91) consists of five power supplies, two motor drivers, eight terminal boards and associated hardware. The primary purpose of the power supply drawer is to provide power to the card cage, motors and emergency wave-off circuits.
Figure 2-91.- Power Supply Drawer Assembly. 2-131 UNCLASSIFIED
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Right Interconnect Junction Box (2A2A4). The right interconnect junction box (figure 2-78) contains twenty-four terminal boards which provide power and signal interconnection points for all system functions other than lighting and system power, which are handled by the left interconnect junction box. The assemblies primary purpose is to provide a junction point for IFLOLS system stabilization and communication signals, but it also provides wave-off and cut signals to the Integrated Launch and Recovery Television Surveillance (ILARTS) system and pitch, roll and Basic Angle (BA) data to the Electronic Cross Hair Stabilization System (ECSS).
PRI-FLY CONTROL PANEL ASSEMBLY, UNIT 3. The Pri-Fly control panel assembly (figure 2-92) provides specific system information and the ability to make changes in various system settings as described below. The unit is bulkhead mounted and consists of a flat panel display module, a display control module, an intensity control module and a shroud base subassembly. Unit 3 control panel also acts as a connection point for the air officer’s “WAVE-OFF” switch and “LIGHTING INTERLOCK” switch (also known as the “LENS OFF/LENS ON“ switch) located in the air officer’s center control console. IFLOLS senses closure of both switches and provides illumination power for these switches.
Flat Panel Display Assembly (3A1A1). The Flat Panel Display assembly (figure 2-92) provides specific system information with four visual display/touch screens: the MAIN screen display, the LIGHTING screens display, the STABILIZATION screen display and the NON-STD (standard) screen display. The flat panel will display all BITE error conditions in the status bar area of all screens.
NOTE
All screen displays for the Pri-Fly control panel are comparable to those previously described in the sections for the Lens Room screen displays. There are subtle differences, such as the NONSTANDARD screen display (Figure 2-93) in Pri-Fly includes a MOVLAS function that is not included in the Lens Room.
The Pri-Fly control panel does not include screen displays for the MODE/STATUS, CALIBRATION and POLE CHECK screen displays.
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Figure 2-92.- Pri-Fly Control Panel Assembly.
Figure 2-93.- Pri-Fly NONSTANDARD Screen Display. 2-133 UNCLASSIFIED
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Pri-Fly Nonstandard Screen Display. The Pri-Fly NONSTANDARD screen display (figure 2-93) shows the status bar, which is the same as on the MAIN screen. This screen permits the air boss to manually change the hook path, the basic angle and the hook to eye distance, to select nonstandard aircraft types, to save and set two nonstandard configurations and to enable or disable the barricade. Additionally, a separate touch screen area to ENABLE changes. On the right side of the screen are touch screen indications of which other screens can be reached from the current screen, a color scheme button for setting the display to white or red graphics, a BRT RESET (brightness) reset touch screen indication, and a touch screen indicator/switch showing whether Pri-Fly or the lens room has system control, and the ability to take control of the system at Pri-Fly. To make a selection on this screen for the NONSTANDARD AIRCRAFT TYPE, select ENABLE button (the text will change to ENTER and the button will be highlighted), then touch the desired button to activate (the button will highlight to indicate a successful selection) and then select ENTER button. To manually enter a HTD, B/A or a H/E, select ENABLE, one of the three buttons (HTD, B/A, or H/E), use the up and down arrows to select the correct value then hit ENTER. The changes will not be activated until the ENTER button is selected. To activate a BARRICADE button select ENABLE, BARRICADE, A/C TYPE-H/E and then ENTER. To save a H/E setting, select the H/E manually, choose either save SET1 or save SET2 then select ENTER. The saved setting can now be accessed using the button that it was saved under.
LSO CONTROL PANEL ASSEMBLY, UNIT 4. The LSO control panel assembly (figure 2-94) located at the LSO workstation provides the LSO with specific information concerning system and system interface status. The LSO does not have touch screen capability at the control panel since the flat panel has a fixed "weather cover" mounted over it. This cover extends to cover the intensity controls but is hinged and latched for easy access to those controls. The LSO has the ability to change the intensity settings for the system deck edge display on the lighting screen display by switches located on the display control module. In an emergency situation, the LSO can initiate wave-off or cut from this unit. The assembly consists of a flat panel display, display control module, intensity control module and a shroud base subassembly. (If Service change 7 - Landing Signaling Officer Display (LSOD) is incorporated, omit LSO control Panel Assembly part number 3429AS0400- 2)
Flat Panel Display Assembly (4A1A1). This assembly (figure 2-94) provides the LSO with two unique visual display screens: a main screen and a lighting screen. The two screens are modified versions of the system MAIN screen and system LIGHTING screen as found at the lens room and Pri-Fly control panels. 2-134 UNCLASSIFIED
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Figure 2-94.- LSO Control Panel.
LSO Main Screen Display. The LSO main screen display (figure 2-95) graphically represents a hook-to-ramp meter and a Hook Touch Down (HTD) meter. Both meters display dynamic and static information. Additionally, a barricade indicator and targeted wire information are displayed. Across the screen in larger letters is displayed the A/C type, H/E, BA, "FAILURE" message and wave-off indication. This screen also provides two lines of text, which are only displayed under certain conditions; line four will indicate a major system FAILURE and the fifth line will indicate that WAVE-OFF has been initiated.
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Figure 2-95.- LSO MAIN Screen Display.
LSO Lighting Screen Display. The LSO lighting screen display (figure 2-96) has three areas providing information: the status bar, which has thirteen discrete data elements: aircraft (A/C) type, Hook-to-Eye (H/E) distance, Basic Angle (BA) setting, which wire is optimal and its distance from the round down, system stabilization mode, system status, FAILURE MODE, where system failures will be indicated, Air Officer (A/O) interlock status, whether a Hook-to-Ramp (H/R) warning has been issued, status and frequency of the system low cell flash capability, whether wave-off has been initiated, whether CUT has been initiated and whether the barricade is raised. The screen has graphical representation of intensity for: source light (ten top most cells), low cells (bottom most two cells) and datum/cut wave-off. This screen can be accessed only when the LSO selects one of these three intensity settings to view or change. The screen also provides a graphical representation of ship pitch (trim) and roll (list) gauges (analog and digital) in degrees. To change the intensity for the low cell or source lights, select the appropriate button from the intensity control select block (the button should flash). Press the up and down arrows and the intensity setting should move one level each time the up or down arrows are press. 2-136 UNCLASSIFIED
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The datum, cut and wave-off button works by toggling through the three lighting intensities it controls and highlighting the one that is active at the top of the screen. To select the datum, cut or wave-off lights press the datum, cut and wave-off button until the lights are highlighted at the top of the screen and then select the up and down arrows to change the intensity. When the desired intensities are set, the screen will timeout and return to the main screen.
Figure 2-96.- LSO LIGHTING Screen Display.
HEAVE SENSOR ASSEMBLY, UNIT 5. The heave sensor assembly (figure 2-75 and 2-97) is mounted to the deck in the lens room. The assembly consists of an accelerometer, a power supply and a terminal board. It provides analog heave measurement signals for the IFLOLS system.
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Figure 2-97.- Heave Sensor Assembly.
Accelerometer (5A1). The accelerometer mounted orthogonal to the heave assembly base plate and measures acceleration along the "Z" axis (vertical) (Refer to figure 2-98.)
Figure 2-98.- Ship’s Motion, Pitch, Roll and Heave Axis.
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The main IFLOLS CPU (2A2A2A5) has the ability to differentiate pure ship heave out of the information acquired from the accelerometer and ship’s roll input.
Power Supply (5PS1). The power supply provides ±15 VDC power to the accelerometer.
PORT AND STARBOARD DATUM ARM ASSEMBLIES, UNITS 8 AND 9. The port and starboard datum arm assemblies (figure 2-75 and 2-99), mounted on the deck edge, provide a lighted horizontal datum reference line.
Figure 2-99.- Port and Starboard Datum Assemblies.
The datum arm assemblies consist of a rectangular metal tube containing two terminal boards and ten lamps. The lamps are held in place by lamp retainer and filter assemblies. The filters used for both units are all aviation green.
With respect to the indicator display assembly, the five most outboard lamps in each assembly are fixed datum lights, while the five most inboard lamps in each assembly are called conditional datum lights. When wave-off is initiated, the conditional datum lights are extinguished.
DISTRIBUTION JUNCTION BOX ASSEMBLY, UNIT 10. The distribution junction box assembly (figure 2-75 and 2-100) consists of three electro-mechanical relays, three relay sockets and six terminal boards. Located in the LSO equipment room, near the LSO station, the junction box provides signal and power distribution to the LSO control panel and acts as a tie point for the wave-off indicator monitor.
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Figure 2-100.- Distribution Junction Box Assembly.
The junction box assembly also distributes signals to other systems external to IFLOLS. It provides a distribution point for ship trim, ramp motion and wave-off to the LSO HUD. It also sends a wave-off signal to the AN/SPN-46 radar. The LSO wave-off panel switch and portable switch assemblies are also connected to IFLOLS via Unit 10.
PORT AND STARBOARD WAVE-OFF/CUT LAMP ARM ASSEMBLIES, UNITS 11 AND 12. The port and starboard wave-off/cut lamp arm assemblies (figure 2-101) consist of eight lamp-housing assemblies each.
Cut Lights. In both units the two top most lamps, side by side, utilize aviation green filters and are CUT lights.
Wave-Off Lights. The three lamp housings, utilizing red filters and mounted vertically on the outboard side of both units, with respect to the indicator display assembly, constitute the wave-off lights.
Emergency Wave-Off Lights. The three lamp housings, utilizing red filters and mounted vertically on the inboard side of both assemblies with respect to the indicator display assembly, constitute the emergency wave-off lights.
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Figure 2-101.- Port and Starboard Wave-Off/Cut Lamp Arm Assemblies.
EMERGENCY WAVE-OFF CONTROL PANEL ASSEMBLY, UNIT 13. This assembly (figures 2-75 and 2-102) is also known as the master wave off control panel assembly and is the signal processing, distribution and control center for the wave-off light system. It works integrally with the IFLOLS system and is located in the lens room. The front panel assembly consists of indicators, switches and circuit breakers. Opening the hinged front panel assembly accesses the card cage assembly, a step-down transformer and terminal boards.
The emergency wave-off control panel (figure 2-102) also provides 115 VAC emergency wave-off power to the IFLOLS system at the lighting junction box assembly (Unit 15). The junction box assembly in turn provides emergency wave-off power to port and starboard wave-off/cut lamp arm assemblies (Units 11 and 12 respectively) and the wave- off monitor (Unit 18) as soon as Unit 13 is energized. The emergency wave-off control panel also provides a signal to the lens room control panel (Unit 2) and then to the distribution junction box assembly (Unit 10), from which systems that interface with IFLOLS can determine where wave-off was initiated.
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Figure 2-102.- Emergency Wave-Off Control Panel.
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LIGHTING JUNCTION BOX ASSEMBLY, UNIT 15. The lighting junction box assembly (figure 2-75 and 2-103), located on the deck edge, provides electrical connection points for IFLOLS wave-off, emergency wave-off and cut lighting components. The assembly consists of an enclosure and two terminal boards.
Figure 2-103.- Lighting Junction Box Assembly.
TRANSFORMER ENCLOSURE ASSEMBLY, UNIT 16. The transformer enclosure assembly (figure 2-75 and 2-104), located on the deck edge, consists of four transformers and three terminal boards. The assembly provides 20 VAC to the indicator display assembly lamps and 28 VAC to the port and starboard datum arm lamps.
Figure 2-104.- Transformer Enclosure Assembly. 2-143 UNCLASSIFIED
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WAVE-OFF INDICATOR MONITOR ASSEMBLY, UNIT 18. The wave-off monitor (figure 2-105) consists of a red domed aircraft warning light and is of the approximate dimensions given in table 2-13. There are two wave-off monitor assemblies, one located on forward side of Unit 12 and the other located aft of the LSO workstation. They flash at the same rate as the wave-off lights and provide an indication, which can be seen in the LSO workstation, Pri-Fly and bridge areas that a wave-off has been initiated.
Figure 2-105- Wave-Off Indicator Monitor Assembly.
LSO PORTABLE SWITCH ASSEMBLY, UNIT 17. The portable "PICKLE" switch assembly (figure 2-106) consists of a pistol-grip type handle, a gray push-button switch (cut light switch) and a red push-button switch (WAVE-OFF light switch). The portable switch assembly permits the LSO to control the operation of cut lights, wave-off lights and emergency wave-off lights from points other than the LSO panel. There are three LSO portable switch assemblies available at any time for use in initiating cut lights, wave-off lights or emergency wave-off lights.
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Figure 2-106- LSO Portable Switch Assembly.
PRI-FLY IFLOLS/CROSS CHECK ENCLOSURE ASSEMBLY.
Pri-Fly Workstation. The Pri-Fly cross check workstation (figure 2-107) uses identical components for the IFLOLS touch screen display and the arresting gear operator’s touch screen display. This cross check design will allow the IFLOLS and A/G screens to be displayed on either side of the integrated workstation. The size and layout of this workstation was designed such that one operator can easily operate both IFLOLS and A/G cross check. The layout will also allow separate operators to operate IFLOLS and A/G cross check.
Figure 2-107- Pri-Fly Cross Check Workstation.
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Cross Check Dimmer Panel Assembly. The dimmer panel assembly provides system on/off and intensity control for the cross check flat panel display, the display control module and the EL backlighting panel of the intensity control module. The module consists of a voltage regulator assembly power switch and two potentiometers.
3.5 Inch Floppy Drive Assembly. The 3.5-inch floppy drive assembly allows recovery log data to be downloaded to a 3.5-inch floppy disc that can be uploaded to the ASRL program.
Card Cage Assembly. The card cage assembly contains four circuit cards necessary for system operation.
a. 16 Channel Digital Output Card.
b. Synchro to Digital Converter Card.
c. CPU Circuit Card.
d. Serial Communication Circuit Card.
Cross Check Flat Panel Assembly (A5). The Pri-Fly A/G cross check flat panel assembly allows the entering of data to initialize the system to enter sunrise and sunset times, to pre-enter a list of aircraft side numbers and miscellaneous data as appropriate. This data will typically be entered when the system is initially powered up and then updated at least once each operational day during the pre-ops of the system. During recovery operations, the flat panel assembly allows the A/G engine weight settings to be automatically set and then verifies that all engines are properly set, sub-systems are in "Battery" and performs the cross check function of verifying that the arresting gear and Improved Fresnel Lens Optical Landing System (IFLOLS) are both set for the same aircraft type.
MOVLAS Operations Entry Screen. If MOVLAS is being used, the A/G Pri-Fly operator must enter this into the cross check system so that the system does not try to get a cross check verification with IFLOLS.
NOTE Paragraphs 156/157 are applicable to installations with IFLOLS S/C 4 and A/G S/C 440 installed.
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(A/G) Pri-Fly Operations Panel. The installation of a dual opto-isolated RS-485 communication card allows transmission of IFLOLS hook-to-eye and basic angle information to A/G cross check. If the IFLOLS settings match the required settings for the aircraft type selected on the A/G panel, the LENS symbology on the air officer's panel displays in green.
2.9.0 MANUALLY OPERATED VISUAL LANDING AID SYSTEM (MOVLAS) The MOVLAS is a backup visual landing aid system used when the primary optical system (IFLOLS) is inoperable, when stabilization limits are exceeded or unreliable (primarily due to extreme sea states causing a pitching deck), and for pilot/LSO training. The system is designed to present glide slope information in the same visual form presented by the IFLOLS.
There are three installation modes aboard ship: STATION 1 is immediately in front of the IFLOLS and utilizes the IFLOLS wave-off, datum, and cut light displays. STATION 2 and 3 are independent of the IFLOLS and are located on the flight deck port and starboard side respectively.
2.9.1 MOVLAS Components
Lightbox MOVLAS is a vertical series of orange lamps manually controlled by the LSO with a hand controller to simulate the ball.
Hand Controller The hand controller is located at the LSO workstation. A handle is provided so the LSO may select the position of the meatball. The pickle switch is attached to the end of the controller handle. As the handle on the LSO controller is moved up or down it lights three or four consecutive lamps in the light box thus providing a meatball.
Repeaters MOVLAS repeaters show where the LSO is displaying the meatball to the pilot. One repeater is displayed on the Integrated Launch And Recovery Television Surveillance System (ILARTS). 2-147 UNCLASSIFIED
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2.9.2 IFLOLS MOVLAS Mode MOVLAS mode is chosen when the IFLOLS cannot utilize active mode while air operations are being performed. This mode needs to be chosen, it is not an automatic mode selected by the IFLOLS.
a. Utilize MOVLAS mode: during periods of rough seas when the IFLOLS can no longer stabilize (pitch angle greater than +/- 1.62 degrees or roll +/- 8.19 degrees) and the system exits the active mode and enters the calibration mode.
b. When MOVLAS mode is chosen, the s ource and low cell lights will be turned off and the datum lights will turn on and return to their original intensity setting.
c. The port and starboard DC motors (in Unit 1) are disabled in the MOVLAS mode.
d. While in the MOVLAS mode, th e dynamic hook-to-ramp and hook touchdown meters will operate up to the graphical limits on the main screen display at all stations. If these limits are exceeded, the display will stop at the extreme and resume when the reading(s) fall back within the graphical range.
e. MOVLAS mode allows for +/- 2.5 degr ees of ship’s pitch and +/- 10 degrees of ship’s roll without giving an alarm.
f. The System status area on the flat panel screen will display “MOVLAS” on the first line (A/C hook to eye) and the system mode line.
g. Basic angle and hook touchdown values can still be entered.
h. When the MOVLAS button is selected the button grid for hook to eye values will be disabled.
i. Commanded position will be sent back from the stabilization computer instead of the feedback position.
j. The HUD display and the ILARTS interface are active in MOVLAS mode.
k. To exit the MOVLAS mode, sele ct ACTIVE or CALIB from the MODE/STATUS screen in the lens room. 2-148 UNCLASSIFIED
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2.10.0 INTEGRATED LAUNCH AND RECOVERY TELEVISION SURVEILLANCE SYSTEM (ILARTS)
2.10.1 Overview The Integrated Launch and Recovery Television Surveillance (ILARTS) System monitors/records day and night flight ops via LLL (Low Light Level) Cameras located at key locations on the carrier. Each of the LLL cameras operates from full daylight (100,000 lux) to night (.001 lux). The primary requirements for ILARTS are:
a. Provide video to assist in incident analysis.
b. Allow the Landing Signal Officer (LSO) to detect flight path deviations and coordinate pilot/aircraft approach maneuvers.
c. Directly assist the LSO during recoveries, by providing real-time glide-slope / alignment information.
d. Enhance the abilities / capabilities of key activities onboard the ship by providing live video during flight ops. (CIC/AIR OPS, CIC/CACC, PILOT HOUSE, THE FLAG BRIDGE, PRIMARY FLIGHT CONTROL, FLIGHT DECK AMCC, and the LSO PLATFORM)
2.10.2 Island Camera Installation The Island Camera is located 40 feet above the flight deck on the island structure. The operator positions the LLL camera on the aircraft and manipulates the zoom from 4 to 40 degrees to maintain proper framing of the aircraft. The Island Camera is used to identify the aircraft and the arresting wire engaged during recoveries. The Island Camera also covers launches and other key flight deck activity. The island camera unit is mounted on a pedestal equipped with a manually operated pan and tilt head; this, of course, requires that an operator be present in the island camera booth. The island camera station is protected by an enclosure. The enclosure is equipped with red and white lighting, and a jackbox for connection of a sound-powered telephone headset to provide audio communication with the ILARTS control room. 2-149 UNCLASSIFIED
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2-150 UNCLASSIFIED CENTERLINE INSTALLATION Two LLL Cameras identified as “Aft” and “Forward” are located at selected positions along the angled deck centerline to provide glide-slope and line-up data during aircraft approach. Both cameras provide 14 degrees 35-minutes horizontal and 10 degrees 58- minutes vertical field of view. Each of the centerline camera installations is enclosed in a compartment approximately 6-feet by 6-feet; the compartment is equipped with a locking access door, 120Vac utility outlets for operation of test equipment and portable power tools for maintenance purposes, a 125-psi air supply line with shut-off valves for clearing lens obstructions, piping connections to ship's drain, and a jackbox for connection of sound-powered telephone headset for audio communication to the ILARTS control room.
DECK-EDGE CAMERA INSTALLATION
Three LLL Cameras aided by infrared illuminators for night operations are employed for catapult surveillance. Each camera is used to view catapult launch operations, and specifically to record aircraft tow bar engagement into the catapult shuttle spreader. The cameras zoom lens, infrared illuminators, and pan / tilt unit allows the operator to maintain proper coverage of the aircraft.
2.10.3 Control Room All ILARTS cameras are operated from the control room, which contains equipment required for processing, control, and synchronization of the video information. The control room also contains equipment for switching, recording, and distribution of the video signals, as well as the audio signal obtained from the LSO radio to the appropriate activities onboard the ship. The room must be air-conditioned, as the heat dissipation of the ILARTS equipment is about 10 kW. A sound-powered telephone circuit from the control room to the island camera station and each of the centerline camera compartments is required to provide audio communication during operation and maintenance of the system. It is also used for shipboard intermediate level maintenance of the ILARTS equipment. A workbench, cabinets, and stowage space is required for intermediate level maintenance tools and test equipment.
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DECK-EDGE SURVEILLANCE CAMERAS ISLAND CAMERA ROOM CENTERLINE CAMERA VIEW ILARTS provides video to: CIC/AIR OPS CIC/CACC PILOT HOUSE THE FLAG BRIDGE PRIMARY FLIGHT CONTROL FLIGHT DECK AMCC LSO PLATFORM
CENTERLINE CAMERA INSTALLATIONS ILARTS CONTROL ROOM Figure 2-108- INTEGRATED LAUNCH AND RECOVERY TELEVISION SURVEILLANCE SYSTEM 2-151 UNCLASSIFIED
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The ILARTS system is a replacement for the Mk 1 Mod 4 landing signal officer (LSO) pilot landing aid television (PLAT) system (fig. 2-109) currently in use aboard U.S. Navy aircraft earners. The PLAT system is becoming logistically unsupportable. The primary purpose of the ILARTS system, as with the PLAT system, remains the simultaneous monitoring and recording of aircraft recovery operations, both day and night, as a debriefing medium for pilots and for detailed accident analysis. In addition, programmed servo control equipment and additional camera control equipment required for a catapult launch surveillance system being developed can be accommodated within the equipment racks and control console and fully integrated into the video switching, recording, distribution, and display equipment provided.
Figure 2-109- ILARTS installation location. 2-152 UNCLASSIFIED
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2.10.4 System Description The ILARTS system is a closed television circuit to monitor aircraft landings aboard U.S. Navy aircraft carriers during both day and night operations, and is planned for expansion to include surveillance of launch operations. Three low-light level television (LLLTV) camera chains, each of which is comprised of a camera head unit (CHU), a camera control unit (CCU), and a remote control panel (RCP), are used in the present system. Two of the CHUs are located at selected positions along the angled deck centerline to provide glide slope and line-up data during the approach. Each of the two centerline CHUs is equipped with a 120mm fixed focal length lens, which provides approximately a 14-degree (horizontal) by 10-degree (vertical) field of view.
The centerline CHUs are mounted vertically (below and perpendicular to the flight deck) and view the flight deck through the deck fixture. The deck fixture contains the viewing aperture (window) and a mirror assembly, which provides a means of setting the optical axis (of the 120mm lens/CHU assembly) parallel to the optical glide slope of the incoming aircraft (fig. 2-109).
The remaining CHU is located above the flight deck level on the island structure, which provides an unobstructed view of the flight deck. This CHU is used to identify the aircraft and the arresting wire engaged. It is also used to monitor launch operations, accidents, and other flight deck activity. The island camera CHU is equipped with a motor-operated 10:1 zoom lens. The camera housing contains the operator’s viewfinder (monitor) and zoom control. The island camera unit (CHU, zoom lens, and housing) is mounted on a pedestal equipped with a manually operated pan and tilt head (fig. 2-109). This, of course, requires that an operator be present in the island camera booth. The control of the CHU itself is accomplished in the same manner as the centerline CHUs. The CHUs are controlled from a centralized control room that contains equipment required for processing, control, and synchronization. The control room also contains equipment for switching, recording, and distribution of the video signals, as well as audio signals obtained from the LSO radio. Monitoring equipment consisting of a 9-inch or 17-inch monitor and 1-watt loudspeaker are located in each of the selected spaces throughout the ship.
2.10.5 System Installation The shipboard installation of the ILARTS system consists of two centerline camera installations; an island camera station; a centralized control room; and a remotely located monitor installed in the pilot house, each of the squadron ready rooms, and other designated spaces. The general arrangement of the system is shown in figure 2-109.
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Centerline Camera Installation Two centerline camera installations, identified as Aft and Forward are required to accommodate the range of hook-to-eye values of the various aircraft, and the resultant vertical displacement of the optical glide path. Each of the centerline camera installations is enclosed in a compartment approximately 6-feet by 6-feet, The compartment is equipped with a locking access door; utility outlets at 115 volts, 60 Hz, single phase for operation of test equipment and portable power tools for maintenance purposes; a 125-psi air supply line with shut-off valves; piping connections to ship’s drain; and a jackbox for connection of sound-powered telephone headset for audio communication to the ILARTS control room.
Island Camera Station
The island camera station is located on the ship’s island structure approximately 40 feet above the flight deck. The island camera station is protected by an enclosure. The enclosure is equipped with 115-volt ac utility outlets for maintenance purposes; red and white lighting; space heaters or forced hot air to keep the enclosure dry when not in operation; drainage facilities for removal of water that may accumulate during operation; and a jackbox for connection of a sound-powered telephone headset to provide audio communication with the ILARTS control room. In addition, electrical power at 115 volts, 60 Hz, single phase, 10 amperes is required for operation of the viewfinder monitor and zoom lens control of the island camera housing.
Control Room
The ILARTS control room contains all equipment required for operation, control, switching, and distribution of video and audio signals. It is also used for shipboard intermediate level maintenance of the ILARTS equipment. The room should be air- conditioned. The heat dissipation of the ILARTS equipment is 10 kW. A sound-powered telephone circuit from the control room to the island camera station and each of the centerline camera compartments is required to provide audio communication during operation and maintenance of the system. A workbench, cabinets, and stowage space is required for intermediate level maintenance tools and test equipment.
Remote Monitors
Television monitors and loudspeakers are installed at various designated spaces.
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2.10.6 System Interface Requirements The ILARTS system interfaces with other shipboard equipment according to the following:
Table 2-15- ILARTS Interface Requirements. 2-155 UNCLASSIFIED
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2-156 UNCLASSIFIED 2.11.0 SUMMARY In this chapter, we have described the purpose and operation of the ship’s Aviation Equipment Systems. We have identified and discussed the function of the Stabilized Glide Slope Indicator (SGSI) System, various Wave-Off Light Systems, Vertical and Short Take-Off and Landing Optical Landing Systems (VSTOL OLS), Improved Fresnel Lens Optical Landing System (IFLOLS), Manually Operated Visual Landing Aid System (MOVLAS), and the Integrated Launch and Recovery Television Surveillance System (ILARTS). We have briefly discussed some of the preventive and corrective maintenance measures associated with the ship’s Aviation Equipment systems.