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28 Cards in this Set
- Front
- Back
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What is Pascals law?
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A confined body of fluid exerts equal pressure at every point and in every direction in the fluid and acts at right angles to the enclosing walls of the container.
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What are the primary and secondary purposes of an accumulator?
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1. Dampen pressure surges
2. Store an amount of fluid under pressure to assist engine driven pump in times of high workload/fluid demand. |
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What is the purpose of a check valve?
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Ensures no fluid flows in the wrong direction.
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How does a constant displacement pump work?
What are its limitations? |
Pumps fluid and is directly proportional to engine speed. Pressure relief valve regulates pressure.
Limited to about 1500PSI (not enough for large planes) |
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How does a variable displacement pump work?
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Pumps fluid and regulates pressure.
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What is pre-charge pressure?
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Measured when system is depressurised. Engineers pressurise accumulator to about 40% of normal hydraulic operating pressure.
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Which hydraulic system component sense over-pressures and returns excess fluid to the reservoir?
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Relief valve
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Which hydraulic system component is located downstream of the pump and signals pump to kick-in/kick-out?
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Pressure switch
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What causes sludge to build up in hydraulic fluid?
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Operating outside prescribed temperature limits.
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Name the two different types of fluid cooling methods.
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Tubing heat exchanger
Radiator type heat exchanger |
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What is the part named "U"?
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A combination filter and heat exchanger.
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What is the part named "R"?
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Manually operated isolation valve. Automatic shut off occurs when fire handle is operated by the crew.
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What is the part named "S"?
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A breaker switch which will automatically extinguish any low pressure light in the cockpit when the isolation valve has been activated.
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What is the part named "A"?
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Accumulator
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What is the part named "B"?
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Engine driven pump
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What is the part named "E"?
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Electrical pump
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What is the part named "A"?
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Reservoir
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What is the part named "B"?
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Engine driven pump
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What is the part named "C"?
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Electrical driven pumps
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What is the part named "A"?
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A supply line
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What happens to the braking hydraulic system if the right system depressurises due to a fault?
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Shuttle valves automatically close off the normal supply and allow the centre system to power the brakes.
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What four protections are provided by the anti-skid controller?
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1. Anti skid
2. Locked wheel 3. Hydroplane 4. Touchdown |
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How does the anti-skid controller work?
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Regulates hydraulic pressure through each valve, based on eight separate wheel speed transducer inputs.
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How can the park brake be set when there is no active hydraulic pressure to both the right and centre systems?
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A brake accumulator in the normal brake system can apply pressure.
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What happens to the brake accumulator in the normal system when the right hydraulic system fails?
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Brake accumulator pressure is maintained by an isolation valve, preserving accumulator pressure for use should the centre system fail.
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What services are available by the brake accumulator only (assuming right and centre system failures)?
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Several applications of the brakes
Anti-skid protection |
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When will the "Brake Source" light illuminate?
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When both right system and centre system hydraulic pressure is low. Accumulator is only source of braking power (the reserve system).
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What system powers the nose wheel steering?
What happens if this system loses pressure? |
Centre system powers nose wheel steering.
Reserve system provides nose wheel steering in case of failure of centre system. |
