13. Hydraulics Flashcards
Where can you monitor hydraulic quantity and pressure?
STATUS page or Hydraulic Synoptic display.
How many independent hydraulic systems are there?
Three
Which of the hydraulic systems primary power source is powered by: - a. Engine driven pumps (EDPs)?
b. Electric motor pumps (EMPs)?
a. Left and right b. Center
What type of pumps are the left and right demand pumps?
Electric motor pumps (EMPs)
Which hydraulic system or systems normally power the following services: a. Flight controls?
b. Nose gear steering?
c. Landing gear actuation?
d. Right and left wing spoilers? e. Flaps & slats?
a. All three b. Center c. Center d. All three e. Center
When selected to AUTO, when do the L and R demand pumps run
• System low pressure
• On the ground for the first three minutes after the second engine is
started
• From takeoff thrust set to flaps retracted
• During descent from when the gear lever is down and radio altitude is
less than 1000 feet until groundspeed is less than 40 knots • Thrust reverser operation
When selected to AUTO, do C1 and C2 primary pumps run continuously?
No, the two center pumps alternate as a primary pump and demand pump
When does the first center system pump start running continuously?
After the second engine is started
Under what circumstances would the second center pump run?
• System low pressure
• On the ground for the first three minutes after the second engine is
started
• From takeoff thrust set until radio altitude exceeds 2000 feet
• Flaps or slats are in motion
• During descent from when the gear lever is down and radio altitude is
less than 2000 feet until groundspeed is less than 60 knots
Why does the Centre hydraulic system have an isolation feature?
To ensure, in the event of a leak, the flight crew can lower the landing gear and that nose wheel steering is operational for landing, roll-out and taxi
When would the shut-off valves supplying fluid from the left and right reservoirs to the engine driven pumps be closed and the engine driven pumps depressurised?
When the appropriate Fire Handle is pulled
When would the Ram Air Turbine (RAT) deploy automatically?
• Both engines have failed
• All three hydraulic system pressures are low
• Loss of all electrical power to captain’s and first officer’s flight
instruments
• Loss of all four EMPs and faults in the flight control system occur on
approach
• Loss of all four EMPs and an engine fails on takeoff or landing
What systems does the RAT provide hydraulic power to?
The primary flight controls connected to the center hydraulic system
