29 Hydraulic Flashcards
Green hydraulic reservoir capacity?
14.5L
Blue hydraulic reservoir capacity?
6.5L
Yellow hydraulic reservoir capacity?
12.5L
Which systems have an accumulator?
All three!
What is the hydraulic system pressure normally? (and when supplied by the RAT?)
3000psi +/- 50psi
2500psi if supplied by RAT
When does the pressure displayed on the HYD SD page turn amber?
<1450psi
When does the PTU kick in?
With a difference of 500psi between Green/Yellow system
What is the hydraulic fluid ignition point?
450degC
Where does the air come from to pressurise the hydraulic reservoirs and why?
HP bleed from engine 1 and to prevent cavitation
What are priority valves used for in the hydraulic system?
To cut off hydraulic power to heavy load users if hydraulic pressure in a system gets low
Which hydraulic system has a hand pump and why?
Only the yellow, for the cargo door
On the HYD SD page, what does the circle represent towards the bottom of the Green and Yellow systems?
The hydraulic fire shut off valve (controlled through FIRE PB)
What do the squares on the HYD SD page system lines represent?
Engine 1 + 2 (G + Y) engine driven hydraulic pumps, and the blue electric pump
Which are the heavy load users that the priority system can isolate?
Green: Landing Gear, Slats + Flaps
Blue: Emer Gen, Slats
Yellow: Flaps
Which systems use green hydraulic pressure to operate?
Landing Gear
Slats and Flaps
Rev Eng 1
Normal Brakes
Yaw Damper 1 Rudder Stabiliser L Elevator L + R Spoiler 1 L + R Spoiler 5 L + R Aileron L + R Slat WTB R Flap WTB
Which systems use blue hydraulic pressure to operate?
Emer Gen
Slats
Rudder L + R Flaps WTB L + R Slats WTB L + R Elevator L + R Spoiler 3 L + R Aileron
Which systems use yellow hydraulic pressure to operate?
Flaps
Nose Wheel Steering Alternate/Parking Brake Rev Eng 2 Yaw Damper 2 Rudder Stabiliser R Elevator L + R Spoiler 2 L + R Spoiler 4 L Flap WTB
Can systems be recovered in a green and yellow hydraulic system failure? How?
Engine driven pump fail? Possibly use yellow electric pump
Low reservoir air pressure? System recoverable at lower altitudes
Reservoir overheat? Useable for approach once cooled
What are the key considerations for a green and yellow hydraulic system failure?
Stopping problem (landing distances almost triple) Alternate law (direct law at gear down) Gravity gear extension QRH Flaps/slats locked QRH Some systems may be recoverable
Can systems be recovered in a blue and yellow hydraulic system failure? How?
Engine driven pump fail? Yellow electric pump or RAT for blue system
Low reservoir air pressure? System recoverable at lower altitudes
Reservoir overheat? Useable for approach once cooled
What are the key considerations for a blue and yellow hydraulic system failure?
Normal law (but without autopilots)
Gravity gear extension QRH (to protect green)
Nose wheel steering is lost
Can systems be recovered in a green and blue hydraulic system failure? How?
Blue electrical pump fail? RAT out
Low reservoir air pressure? System recoverable at lower altitudes
Reservoir overheat? Useable for approach once cooled
What are the key considerations for a green and blue hydraulic system failure?
Handling problem (gear at 200kts)
Aircraft sluggish
Gravity gear extension QRH (at 200kts)
Flaps/slats locked QRH
What should you turn off if you have a G hydraulic low level or low air pressure?
The PTU to prevent it overheating or damaging the other system, and the green engine 1 pump
What should you turn off if you have a Y hydraulic low level or low air pressure?
The PTU to prevent it overheating or damaging the other system, the yellow engine 2 pump, and the yellow electric pump
