E175 Hydraulics Flashcards
How many hydraulic systems are on the airplane?
- 3 Independent systems
- HYD 1, HYD 2, and HYD 3
What systems use hydraulic power?
- Flight controls
- Spoilers
- Landing gear
- Nose wheel steering
- Wheel brakes
- Thrust reversers
Can hydraulic fluid be transferred between each system?
No
How many hydraulic pumps are onthe airplane?
- 6 total
- 2 EDPs (Engine Driven Pumps)
- 4 ACMPs (AC Motor Pumps)
What are the basic components of the hydraulic systems?
- 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 on the ground?
Flaps > 0, and TL set to T/O, or Groundspeed > 50 kts
When will ACMP 1 or 2 automatically activate in the air?
- Engine failure or EDP failure
- Flaps > 0
What are some important items controlled by HYD 2 system?
- Elevator (L & R Inboard)
- Ailerons (L & R Inboard)
- Thrust Reverser (Engine 2)
- Multi-Function Spoilers(L & R panels 5)
- Ground Spoilers (L & R panel 1)
- Brakes (Inboard)
- Landing Gear
- Nose Wheel Steering
- Emergency Parking Brake
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 takeoff and landing with flaps > 0, if Engine 2 fails, or EDP 2 fails
How is single engine taxi possible if nosewheel steering is on HYD 2?
Releasing the parking brake activates ACMP2
What is the primary purpose of HYD 3 system?
Back-up for the Flight controls
Why are HYD ACMP 3A & B pump switch positions ON & 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
