Oral: Hydraulics Questions Flashcards
Know
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 on the airplane?
•6 total:
1) 2 EDPs (Engine Driven Pumps
(2) 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?
• Ground
1) Flaps > 0, and
2) TL set to T/O, or
3) Groundspeed > 50 kts
• Flight
1) Engine failure or EDP failure
2) Flaps > 0
What are some important items controlled by 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 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 > 0, if
1. Engine 2 fails, or 2. EDP 2 fails
How is single engine taxi possible if nosewheel 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 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
