Hydraulic

Question 1

When is PTU inhibited?

Answer 1

40 s after the end of cargo door operation.

Between the first and second engine start.
Automatically tested during the second engine start.

Question 2

When does RAT drops out?

Answer 2

If AC BUS 1 and AC BUS 2 are both lost.

Question 3

Priority Valves

Answer 3

Cuts off supply to heavy users (Slats, Flaps, Landing Gear, Emergergency Generator, NWS on old aircraft), if pressure is low.

Question 4

Fire Shutoff Valves

Answer 4

Controlled by Fire Pb, only available in Green and Yellow Systems.

Question 5

Leak Measurement Valves

Answer 5

Located upstream of primary flight controls, which is used to determine whether leak is upstream (Hydraulic System) or downstream (Aircraft Systems). (When valve is closed, if system pressure indicates no leakage after pressurization, it is the downstream which has leakage.).

Shutoff Hydraulic Supply to Primary Flight Controls.

Question 6

What supplies pressure of ALL hydraulic reservoirs?

Answer 6

ENG 1 Bleed.

Question 7

Aircraft tail with NWS by yellow system?

Answer 7

HSO and HTJ onwards.

Question 8

When does Blue Pump works on ground?

Answer 8

Only if one engine is running, or

Blue Pump OVRD Pb is ON.

*BLUE ELEC PUMP Pb is defaulted at AUTO.

Question 9

What contributes Pump Fault Light stays on when the crew has selected OFF?

Answer 9

As long as Overheat lasts.

Question 10

Hydraulic Fluid Levels

Answer 10

Maximum Blue: 6.5 L
Maximum Yellow: 12.5 L
Maximum Green: 14.5 L

Filling Range Blue: 1.5 L (1.6L, HSL, HTJ onwards)
Filling Range Yellow: 2.5 L (2.6L, HSL, HTJ onwards)
Filling Range Green: 2.5 L (2.6L, HSL, HTJ onwards)

Low Level Blue: 2.4 L
Low Level Yellow: 3.5 L
Low Level Green: 3.5 L

*1 L = 1.056 US Quarts

Question 11

When does Yellow Electric Pump works on ground?

Answer 11

When crew sets the Cargo Door Manual Selector Valve to OPEN / CLOSE Position, or

YELLOW ELEC PUMP Pb is ON.

*YELLOW ELEC PUMP Pb is defaulted at OFF.