Hydraulics Flashcards Preview

blahblah > Hydraulics > Flashcards

Flashcards in Hydraulics Deck (10):
1

What is the hydraulic system comprised of?

1. Engine Driven pump
2. Electrical driven pump
3. reservoir
4. accumulator

2

What systems are on Hyd 1? How is it powered?

A.
1. Elevator (left Outboard)
2. Rudder (upper)
3. Thrust Reverser (engine 1) - onside
4. Multi-function spoilers (panels 3 and4)
5. Ground Spoilers (panel 2)
6. Outboard brake
7. Emergency Parking Brake

B. AC Bus 2

3

What are overheat protections?

100ºC - Hyd (1,2,3) HI TEMP EICAS caution
125ºC - SOV automatically closes, isolating the pump from its respective flow line
145ºC - HYD 1 OVERHEAT EICAS warning
- SOV can be manually commanded through a pushbutton on the hydraulic panel.

4

What protections help during an engine flameout?

FADEC automatically commands the unload of the respective EDP
- reduces hydraulic system pressure
- reduces torque loads on the engine and facilitates a windmill restart

5

When does electric hyd pump 1 activate? Inflight / ground

In-flight:
- EDP or engine fail
- Flaps >0º

Ground:
- Flaps >0º
- Thrust levers set to Take-off
- Ground Speed >50kt

6

What systems are on Hyd 2? How is it powered?

A.
1. Elevator (left / right inboard)
2. Ailerons (left / right inboard)
3. Thrust reverser (engine 2) - onside
4. Multi-function spoiler (panel 5)
5. Ground spoilers (panel 1)
6. Inboard brake
7. Nose Wheel Steering
8. Landing gear (ext / retraction)
9. Emergency Parking Brake

B. AC BUS 1

7

When does electric hyd pump 2 activate? Inflight / ground

In-flight:
- EDP or engine fail
- Flaps >0º

Ground:
- Engine 1 running or start (N2 reaches 40%) and parking brake released.
- pump will turn off automatically if 6 min have elapsed since brake application.
- simply release parking brake to reactivate pump

8

What is the PTU? When does it operate?

Power Transfer Unit:
- Assists in landing gear retraction or extension should the #2 right engine or electric driven pump fail.

PTU activates when:
- Flaps not set to 0, or landing gear not up and locked
- EDP 1 not fail
- Hyd reservoir 2 quantity 12%

9

What systems are on Hyd 3? How is it powered?

A.
1. Elevator (right outboard)
2. Rudder (lower)
3. Ailerons (left / right outboard)

B. AC ESS BUS

10

What prevents RAT overload?

- Unloader Valve: reduces discharge pressure of ACMP 3A during start-up. This reduces the pump torque and therefore reduce the electrical power required to start the pump

- Flow Limiter valve: reduces the amount of flow provided the ACMP 3A. This limits the electrical power that the pump can draw and prevent the electric hydraulic pump from stalling the RAT.