Hydraulics Flashcards
What are the normal hydraulic pressures?
3000 PSI (+/- 200 PSI)
What hydraulic pressure does the RAT provide?
2500 PSI
How does the Hydraulic system generate pressure?
Green system: Eng driven pump, or PTU
Yellow system: Eng driven pump, or PTU, or electric pump, or hand pump.
Blue system: electric pump, or RAT
Can you operate the cargo doors without auto yellow pressure?
Yes, hand pump.
FCOM; Perf; Loading
What is the hydraulic accumulator and which system supplies it?
A way of storing hydraulic pressure for use when no other means of hydraulic pressure is available. Powered by yellow system. Will provide 7 full brake applications. Actuator pressure helps maintain parking brake. Can be recharged by yellow electric pump.
What are the priority valves and what do they do?
Protect against hydraulic low pressure. Prioritise pressure to flaps/slats, emergency generator and landing gear.
How are the hydraulic reservoirs usually pressurised and what is the redundancy?
Bleed air from eng 1. If eng 1 fails, or bleed air pressure too low, system automatically takes air from the crossbleed duct to prevent hydraulic pumps from cavitation.
Which hydraulic systems have FSOV?
Green and Yellow
Which hydraulic abnormal procedures are located in QRH?
Dual hydraulic failure summaries.
Explain how the PTU functions during the engine start procedure?
PTU inhibited during first eng start, self-tests at the beginning of second eng start.
When does PTU operate?
Any time the pressure differential between green and yellow systems is greater than 500PSI, except when inhibited during 1st eng start and for 40secs after cargo door operation.
