Hydraulic Flashcards
How many hydraulic systems are on the airplane?
3 independent systems
What systems use hydraulic power?
Flight controls Spoilers TRs Brakes Nose wheel steering Landing gear ext/ret
Can hydraulic fluid be transferred between each system?
No
How many hydraulic pumps are on the airplane?
6 total: 2 EDPs, 4 ACMPs
What are the basic components of the hydraulic system?
Reservoir
Pumps
Accumulator
What is the purpose of the accumulator?
Helps to maintain constant pressure by covering transient demands
Helps to avoid pump cavitation
When will ACMP 1 or 2 automatically activate?
Ground:
Flaps > 0 and
TL set to TO or Groundspeed > 50kts
Flight:
Engine failure or EDP failure
Flaps > 0
What are some important items controlled by the HYD 2 system?
Landing gear, nose wheel steering, inboard brakes
What is the PTU?
Power transfer unit
Mechanical pump that uses HYD 1 power to provide HYD 2 pressure
What is the primary purpose of the PTU?
To allow landing gear retraction in the event of an engine 2 or EDP 2 failure
When will the PTU automatically activate?
During TO and landing with flaps > 0, if
Engine 2 fails or EDP 2 fails
How is single engine taxi possible if nose wheel steering is on HYD 2?
Releasing the parking brake activates ACMP 2
What is the primary purpose of HYD 3 system?
Back up for the flight controls
Why are ACMP 3A and 3B pump switch positions ON and AUTO respectively?
HYD ACMP 3A pump is primary and has no automation
HYD ACMP 3B pump is a back-up and automatically activates if ACMP 3A fails
What, if any, HYD ACMP will function if the RAT is the only power source?
HYD ACMP 3A only
