MH-60R - Sonar System Flashcards
(21 cards)
Describe the reel and cable assembly
The reel and cable provide the electrical interface between the sonar transmitter/receiver and the transducer and supports the weight of the transducer when deployed with approximately 2550 feet of cable on the reel. One end of the cable is connected to the transducer and the other is connected to the ST/R via a slip ring on the reel. The cable assembly contains cable limit sensors, a dip cycle counter, and is removable from the reeling machine. Cable limit sensors open when less than five to eight wraps of cable remain on the reel. The reel and cable are contained within the reeling machine.
What are the components of the sonar system?
- Reel and cable assembly;
• Cable reeling machine;
• Reeling machine interface unit (RMIU);
• Reeling machine control unit (RMCU); - Transducer assembly (TA);
- Sonar transmitter/receiver (ST/R).
Describe the cable reeling machine
It is a hydraulic hoist that raises and lowers the transducer. It operates from the aircraft utility hydraulic system. The hydraulic motor drives the gear train assembly, which in turn drives the cable and reel assembly. As the cable and reel assembly rotates, the cable is paid out or retrieved, passing over a level wind mechanism, cable stress sensor, and through the cable angle sensor.
What else is included in the cable reeling machine?
The hydraulic control assembly controls the speed and rotational direction of the hydraulic motor, which is part of the electro-hydraulic servo system that includes the RMIU and RMCU. The unit is equipped with an auxiliary electrical motor and auxiliary hydraulic control system. The auxiliary hydraulic control system provides the capability to raise or lower the transducer in the event of a loss of normal reeling machine control. The auxiliary electric motor provides the capability to raise the transducer in the event of a loss of hydraulic power. The reeling machine also has a cable cutter assembly to cut the sonar cable in an emergency.
What do the cable angle sensors do?
Mounted on the reeling machine measure the angle of the sonar cable relative to vertical when the transducer is deployed. These signals are provided to the Automatic Flight Control System (AFCS) and to the flight displays (for hover mode).
What are the modes of operation for the cable reeling machine?
- Automatic (remote) Hydraulic mode
- Manual (RMCU) Hydraulic mode
- Auxiliary Hydraulic mode
- Auxiliary Electrical mode
- Auxiliary Hardware Electric mode
- Hand Crank mode
What does the Raise Speed Limiter (RSL) do?
It functions with the servo-valve on the hydraulic motor and sends a signal to the servo-valve to ensure that the raise speed does not exceed a set threshold. This ensures a safe approach speed for the TA as it is raised toward the A/C. If the set threshold is exceeded, an appropriate RSL FAIL error will be issued. The RSL does not provide any function during lowering operations, regardless of mode. It does not function during Auxiliary Electrical mode raise operations since electric motor operations do not use the hydraulic servo-valve. It does not function during Auxiliary Hydraulic mode operations because the RMIU part of the function is bypassed and the Auxiliary Hydraulic control limits the speed.
Describe the normal mode of operation for the cable reel machine
Automatic (remote) and Manual (RMCU) Hydraulic modes are the normal dipping sonar operating modes. These modes have full capabilities and full safety features. In these modes, a hydraulic motor drives the gear train assembly, which is connected to the reel and cable. The gear train assembly has a hydraulic clutch that disengages the auxiliary motor assembly when operating in hydraulic mode.
What are the notes associated with the TA at different POCLs?
• RMIU assumes aircraft is at hover height (70 feet).
• Seated, the RMIU reads 0 feet of cable out.
• Trail is six feet below the aircraft (10 feet of POCL).
• 20 feet above water, the RMIU commands the ST/R into ESD protect mode.
• Approximately 28 feet of depth, RMIU detects water entry (SUBMRG advisory light on RMCU) and sends command to ST/R to exit ESD protect mode. (RMIU senses a change of cable tension due to water impact).
• Following a SUBMRG advisory light, DEPTH will be displayed on the RMCU and cable angle display.
• BOTTOM caution light will activate when the TA is within 50 feet of the bottom.
• CBL LIM caution light will activate when the reeling machine senses eight wraps are remaining on the reel.
Decried the Auxiliary Hydraulic Mode of operation
The Auxiliary Hydraulic mode allows the operator to manually control the servo valve in the event of a RMIU failure, bypassing the RMIU and RMCU. This mode bypasses all safety interlocks, does not automatically stop the transducer at the trail position, and does not automatically seat or lock the transducer. A toggle switch on the reeling machine is provided to select either RMIU control or control with the Auxiliary Hydraulic control knob. Operation of the hydraulic motor in manual mode is the same except that the speed range is restricted. This mode provides ner control of the transducer raise/lower speed. Use of the RSL knob limits cable speed to 6 ft/sec when the transducer is within 60 ft of the aircraft. The operator must manually latch the transducer assembly. This mode is used if prescribed by emergency procedures or in the event of electrical power loss. There is no ESD sequence in this mode.
The Auxiliary Hydraulic mode only needs hydraulic power and 28 Vdc essential power to control the reeling machine. This mode is most commonly used for correcting miswraps, reseating the transducer to obtain a SEATED indication, and retrieving the transducer when a fault or failure in the reeling machine control system has occurred.
What are the cautions/notes associated with Auxiliary Hydraulic mode?
CAUTION
• Auxiliary hydraulic mode bypasses all safety interlocks, does not automatically stop the transducer at the trail position, and does not automatically seat or lock the transducer.
• Lowering the transducer into the water using Auxiliary Hydraulic mode will damage system electronics.
NOTE
Use of the Auxiliary Hydraulic mode requires the operator to manually latch the transducer assembly.
Describe the Auxiliary Electric mode
The reeling machine uses the auxiliary motor to drive the gear train assembly. This mode has full safety features and will automatically close the array when raise is selected. It will automatically stop the transducer at the trail position and will automatically seat and lock the transducer when raised into the aircraft. Because of the slower raise speed, the cable is not suf ciently tensioned which may result in problems during normal operation if the TA has been raised from 1000 ft or deeper in Auxiliary Electrical mode. The Auxiliary Electrical mode is used if prescribed by emergency procedures or in the event of a hydraulic fault.
The auxiliary motor receives 115 Vac, 3-phase, 400 Hz power, and electric motor control signals from the RMIU. The 115 Vac provides the power to drive the auxiliary motor assembly. The electric motor control signals select between normal and slow speed. When using the auxiliary motor assembly, the clutch is engaged and mechanically linked to the hydraulic motor resulting in the hydraulic motor running off-load in the raise direction only.
What are the cautions/notes associated with Auxiliary Electric mode?
CAUTION
• Except when executing emergency procedures, Auxiliary Electrical mode shall only be used when TA is submerged.
• If the TA has been raised from 1000 ft or deeper in Auxiliary Electrical mode, the cable should be re-tensioned with normal hydraulic mode before resuming dipping operations.
NOTE
• The Auxiliary Electrical mode has full safety features and will automatically close the array when raise is selected.
• The Auxiliary Electrical mode can only be used for recovery, as this mode only operates in the raise direction.
Describe Auxiliary Hardware Electric mode of operation
The reeling machine uses the auxiliary motor to drive the gear train assembly. This mode bypasses all safety interlocks, does not automatically stop the transducer at the trail position, and does not automatically seat or lock the transducer. The auxiliary motor is controlled directly by the RMCU, circumventing the RMIU electronics. This mode is entered by simultaneously holding the RMCU SAFETY OVERD button and the RMCU RAISE button when in the Auxiliary Electrical mode. The electric motor control is only available in normal speed in this mode, and the raise speed will always be 6 ft/sec. This mode is used if prescribed by emergency procedures or as a last resort to recover the transducer when there are failures that prevent any other mode of operation. When using the auxiliary motor assembly, the clutch is engaged and mechanically linked to the hydraulic motor resulting in the hydraulic motor running off-load in the raise direction only. The auxiliary motor assembly is powered by 115 Vac, 3-phase, 400 Hz power.
What are the cautions/notes associated with Auxiliary hardware electric mode?
CAUTION
-Auxiliary Hardware Electric mode bypasses all safety interlocks, does not automatically stop the transducer at the trail position, and does not automatically seat or lock the transducer.
NOTE
• The Auxiliary Hardware Electric mode can only be used for recovery, as this mode only operates in the raise direction.
• Auxiliary Hardware Electric mode provides only a single raise speed.
Describe the Hand Crank mode of operation
The Hand Crank mode is only used for maintenance purposes. In Hand Crank mode, the hand crank switch on the safeguard assembly is engaged, which disables the hydraulic and Auxiliary Electrical modes. A torque wrench (used to comply with torque limits on the gearbox) is then installed in the hand crank drive of the safeguard assembly to raise and lower the sonar transducer.
Describe the Reeling Machine Interface Unit
The RMIU controls the reeling machine functions, regulates smooth transitions of transducer dipping activities, and performs the reeling machine BIT. The RMIU also provides electrical interfaces between components of the dipping sonar system. There are no controls or indicators on the RMIU. It is on the starboard side of the reeling machine at the rear starboard corner of the aircraft cabin.
What are the functions of the RMIU?
• Snag sense and response;
• Automatic selection of raise and lowering speeds;
• Stop at cable limits;
• Stop at preselected depth;
• Stop at trail position;
• Stop at seat position;
• Stop at kiting condition;
• Stop when excessive water exit speed;
• Stop when transducer is 50 feet from sea oor;
• Stop if uplink data is lost;
• In automatic mode and in “To Trail” commands, folds the array before raising.
Describe the Reeling Machine Control Unit
Contains operating controls and failure indications for the reeling machine and provides the means for lowering and raising the transducer. In AUTO mode, preset depth commands may be issued from a keyset/menu, and acknowledged or canceled via the RMCU. In MAN mode, the SO commands depth changes via the RMCU. The RMCU also contains indicators for monitoring reeling machine control system status.
What are the functions of the Transducer Assembly?
The primary function of the transducer is to transmit the sonar pulse generated by the ST/R and receive the echo returns. It performs the following functions:
• Receives high-power acoustic transmit pulse and WQC transmit signals from the ST/R via the sonar cable and transmits them into the water.
• Receives in-water active echo returns and WQC signals; provides front end processing; converts the signals to digital uplink data; and sends it to the ST/R.
• Processes control signals from the cable downlink to unfold the receive array; folds the receive array; initializes front end attenuation; initiates self-test; and sets transducer mode.
• Provides uplink telemetry through the cable consisting of transducer temperature, depth, azimuth orientation, bottom proximity, vertical inclination, transducer mode, and transducer status.
• Provides hydrodynamic stability during raising and lowering operations at all reeling machine speeds and aerodynamic stability at trail position during aircraft transit.
• Receives in-water wide band energy signals for acoustic signal analysis (ASA) by the AP.
What are the functions of the Sonar Transmitter/Receiver?
The ST/R generates the transmit pulse and provides an interface between the AP and the other SDRS components. It performs the following functions:
• Receives and executes sonar and BIT commands from the AP including active waveform selection, power level, output mode, and initiate BIT.
• Provides operational and BIT status to the AP from the transducer, reeling machine, and ST/R, including current mode, BIT results, fault codes, and ping synchronization.
• Provides a control and status interface with the AP.
• Interfaces with RMIU and RMCU to support remote reeling machine operations.
• Generates high power acoustic transmit waveform for active transmission.
• Receives WQC audio and transmit key from aircraft system and generates a single sideband suppressed carrier signal for WQC transmission.
• Generates downlink command tones for transducer, including commands to unfold and fold transducer array, initialize front end attenuation, initiate self test, and select transducer mode.
• Processes uplink data from the transducer consisting of acoustic receive data, transducer temperature, depth, azimuth orientation, bottom proximity, vertical inclination, transducer mode, and transducer status.
• Formats acoustic receive data and telemetry and sends the results to the AP.
• Provides an interface for real-time recording of acoustic data and reeling machine status.
• Provides an ST/R battle short discrete interface signal to the aircraft system.
