AQC VII: Hydraulic and Pneumatic Systems

Question 1

What systems does the backup hydraulic system not power?

Answer 1

Autopilot
Collective Friction Clutch, Longitudinal hydraulic stop
engine power limiter

Question 2

At what pressure do the hydraulic pumps switch to the operating mode and idle mode?

Answer 2

45 +/- 3

65 +8/-2

Question 3

At what pressure do the main hydraulic pumps switch to the backup mode via the emergency supply valve?

Answer 3

30 +/- 5 kgf/cm2

Question 4

What is the stored air cylinder pressure for the pneumatic wheel brake system?

Answer 4

40-50 kgf/cm2

Question 5

What activates if the hydraulic pump unloading valve fails to switch the pump to idle mode at 65 +8/-2 kgf/cm2?

Answer 5

Pump unloading valve incorporates a safety valve at 78-88 kgf/cm2 (83 +/- 5)

Question 6

What is the purpose of the metering valve in the hydraulic system?

Answer 6

Meters fluid to the hydraulic friction clutch

Shuts off when 400cm3 of fluid pass to prevent fluid loss

Question 7

What supplies fluid to the flight controls in the hydraulic system when the pump is working in idle mode?

Answer 7

Accumulator

Question 8

What is the pressurized air system (PAS) used for?

Answer 8

start the main engines–spin the N1 turbines

Question 9

Where is the gauge for the PAS located?

Answer 9

Pressure gauge in the center overhead console next to EGT temperature

Question 10

When does the automatic pressure switch of the air compressor switch to idle mode? Working?

Answer 10

Idle: 50 kgfs
Operating: 40 kgfs

Question 11

What causes the cockpit starter operating light to illuminate?

Answer 11

When the start control valve opens