Hydraulics Flashcards
What systems are on the Left Hydraulic system?
Flight Controls
Left engine thrust reverser
What systems are on the Right Hydraulic system?
Flight controls
Normal brakes
Right thrust reverser
When do the Lt and Rt HYD DEMAND pumps operate? In the ON position and in AUTO
IN AUTO:
Takeoff
Landing
When system or primary pump pressure is low
The Rt demand pump runs continuously on the ground
ON:
Lt and Rt run continuously
ON THE GROUND:
Which center hydraulic primary pump is shed and when? And when is it not shed?
C2 pump will shed:
With only a single ground power source, including the APU, the C2 pump does not run if the C1 pump is selected
The pump is not load shed:
if one engine generator is operating, or the following sources are operating:
• primary external power and secondary external power or
• APU generator and primary external power
What systems are on the Center HYD system?
The center hydraulic system powers:
• flight controls
• leading edge slats
• trailing edge flaps
• landing gear actuation
• alternate brakes
• nose gear steering
• main gear steering
IN FLIGHT:
When will the primary C2 HYD pump load shed?
• all other electric pumps are running
• there is a single source of electrical power
• generator capacity is exceeded
The pump starts automatically when the conditions that shed the pump no longer exist
When selected in the AUTO position the C1 and C2 air driven DEMAND pumps operate how?
a demand pump operates when system and/or primary pumps pressure is low, or when system logic anticipates a large demand
When selected to ON the C1 and C2 air driven DEMAND pumps operate how?
In the ON
position, the demand pump runs continuously.
Selecting both demand pumps ON
results in only pump C1 operating.
Both pumps cannot operate simultaneously
when ON is selected for both pumps
If center hydraulic system quantity is sensed to be low and airspeed is greater than 60kt, how will the system configure?
• alternate brakes are isolated from the center system and remain operable using reserve fluid
• nose gear actuation and steering are isolated and inoperative
• leading edge slats are isolated and not allowed to operate in the primary
(hydraulic) mode
The leading edge slats are reconnected to the center hydraulic system and allowed to operate in primary mode when:
• center hydraulic fluid quantity recovers to normal for 5 seconds, and
• the system determines that both engines have been running for more than 30 seconds
Nose gear actuation and steering are reconnected when:
• airspeed decreases below 60 knots, or
• hydraulic pressure to the center system flight controls is low, or
• the landing gear is selected down, both engines are normal, and both engine–driven pumps are providing pressure
When will the RAT automatically deploy?
• both engines are failed and center system pressure is low, or
• both AC transfer busses are unpowered, or
• all three hydraulic system pressures are low
The manual deployment of the RAT (pushing the RAT switch) requires one of which two power sources?
The hot battery or APU battery bus must be powered.
The RAT is deployed by a compressed spring. Once deployed, the RAT cannot be stowed in flight
