MH-60R - Systems - APU Flashcards
(12 cards)
What are the sections of the APU?
Power section, a reduction gearbox, appropriate controls, and accessories.
What is the purpose of the APU?
The APU system provides pneumatic power for starting the engines and operating the Environmental Control System (ECS). It incorporates a generator for ground and emergency in-flight electrical operations.
What is fuel consumption rated at for the APU?
150 lbs per hour
When is the APU supposed to be used?
The APU is not intended for routine in-flight use. Operation of the APU in flight shall be limited to essential operations only. Acceptable in-flight use includes emergency procedures, single-engine training, practice autorotations, and powering the ECS during extreme temperature operations.
Warning concerning APU containment device
The APU does not incorporate a compressor or turbine wheel containment device. An uncontained APU failure may result in injury to ground personnel and/or damage to flight critical components including the tail rotor drive shaft.
What is the function of the prime/boost pump?
The prime/boost pump is used to prime the engine or APU fuel lines and provides fuel under pressure to the APU during starting and operations at pressure altitudes above 8,000 feet.
What is the minimum required pressure in the hydraulic accumulator for starting the APU?
2,650 psi
What does the ESU/DESU do?
It controls and monitors the APU. If a start sequence fails or a monitored parameter is exceeded during operation (with the exception of APU OIL TEMP HI), the ESU/DESU will automatically shut down the APU.
How do you maintain BIT codes after failure?
DC power is required and the APU CONTR switch must remain in the ON position.
How does the ESU/DESU display fault codes?
Using Built-In-Test (BIT) indicators. The BIT indicators are capable of displaying start sequence or operation status and specific reasons for APU shutdown.
What does APU FAIL indicate?
Indicates the APU has failed due to high Ng, low Ng, high TGT, low TGT, low oil pressure, or start sequence failure. APU OIL TEMP HI indicates the APU has reached the maximum oil temperature for continuous operation.
What does the DESU for the turbomach/sundstrand do?
It has the added capability to control APU overtemperatures by regulating the main fuel valve and start bypass valve.
