Hydraulics Flashcards
What parts use hydraulic system 1?
Elevator (left, outboard), Rudder (upper actuator), Thrust Reverser (Engine 1), Multi-function Spoilers (Left and right panels 3 and 4), Ground spoilers (Left and right panel 2), Outboard brakes, Emergency Parking Brake
What parts use hydraulic system 2?
Elevator (left and right inboard), Ailerons (left and right inboard), Thrust Reverser (Engine 2), Multi-function Spoilers (Left and right panels 5), Ground spoilers (Left and right panel 1), Inboard brakes, Emergency Parking Brake, nose wheel steering, landing gear
What parts use hydraulics system 3?
Elevator (Right outboard), Rudder (Lower actuator), Ailerons (Left and right outboard)
What is hydraulic system 1 composed of?
A reservoir, an Engine Driven Pump, an AC Motor Pump ACMP used as a back-up for the EDP, and 2 accumulators
What is hydraulic system 2 composed of? How is it different from hydraulic system 1?
The same except: the hydraulic system allows for single-engine taxi. With the selector knob in the AUTO position and only engine 1 operating, releasing the parking brake will automatically activate the ACMP 2 to provide hydraulic power for nose wheel steering and the inboard brakes. The PTU Power Transfer Unit uses hydraulic power from system 1 to provide hydraulic pressure to system 2. With the knob in the auto position the system logic activates the PTU if engine 2 fails or EDP 2 fails to aid in landing gear operation.
What is hydraulic system 3 composed of?
A reservoir, 2 ACMP pumps A and B (pump A is primary (either ON or OFF) pump B is backup (AUTO, ON, OFF where in AUTO the ACMP B will automatically turn on with a failure of ACMP A), 1 accumulator
How does hydraulic system 3 function during an electrical emergency?
The system 3 accumulator will provide hydraulic power to the associated flight controls from beginning of RAT deployment until AC ESS BUS powers the ACMP 3A
When does hydraulic system 1 and 2 ACMPs automatically activate in flight?
System logic activates the ACMP in case of: EDP failure or flaps selected to any position greater than 0 degrees
When does hydraulic system 1 and 2 activate on the ground?
System logic activates the ACMP in case of: flaps selected to any position greater than 0 degrees AND thrust levers set to takeoff thrust OR ground speed greater than 50kts
What the the systems 1 and 2 accumulators used for?
Each system has an accumulator used for shock absorption (transient demands) and another for emergency parking brake use
What is the system 3 accumulator used for?
During an electrical emergency to provide hydraulics to the flight controls
How many hydraulic systems are on the airplane?
3 Independent Systems
What systems use hydraulic power?
flt controls: Flight controls, spoilers
stopping: landing gear, nose wheel steering, wheel brakes, thrust reversers
Can hydraulic fluid be transferred between each system?
No
How many hydraulic pumps are on the airplane?
6 total, 2 EDPs and 4 ACMPs
What are the basic components of the hydraulic systems?
Reservoir, pumps, accumulators
What is the purpose of the accumulator?
Helps maintain a constant pressure by covering transient demands, Helps to avoid cavitation (which can lead to failure) (high vacuum conditions create vapor bubbles within the oil which are carried to the pressure side, collapse, thus cavitation)
When will ACMP 1 or 2 automatically activate on the ground?
Flaps greater than 0, TL set to T/O, or Groundspeed greater than 50kts
When will ACMP 1 or 2 automatically activate in flight?
Engine failure or EDP failure, Flaps greater than zero
What are some important items controlled by HYD 2 system?
Landing gear, nose wheel steering, inboard brakes
What is the PTU?
Power transfer unit, a mechanical pump that uses HYD 1 POWER to provide HYD 2 PRESSURE (No exchange of fluid)
What is the primary purpose of the PTU?
To allow landing gear retraction and extension in the event of an engine 2 or EDP 2 failure
When will the PTU automatically activate?
During takeoff and landing with flaps greater than 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 the HYD 3 system?
Back-up for the flight controls
Why does HYD ACMP 3A pump switch have an ON position and HYD ACMP 3B have an AUTO position?
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