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
What, if any, HYD ACMP will function if the RAT is the only power source?
HYD ACMP 3A only
In an electrical emergency what provides hydraulic pressure to flight controls until the RAT comes online?
- HYD 3 accumulator
- After 8 seconds the RAT will power ACMP 3A
In an electrical emergency can HYD 3 system power requirements overload the RAT?
No. A flow limiter valve is used to reduce flow and limits pump electrical power draw to prevent a RAT stall
