Hydraulics Flashcards
What holds the landing gear in the retracted position?
Nitrogen charged accumulator maintains hydraulic pressure
How is nosewheel steering accomplished?
Direct linkage and differential braking
Describe the hydraulic system?
Electrically driven, hydraulically actuated
Hydraulic system components
•Power package
•Service tray assembly
•Accumulator
•Time delay relay
•Nitrogen pressure cylinder
How long would the gear be held up after a power package failure?
Up to 200 minutes
Where is the hydraulic power package and what does it do?
LH wing root behind the spar
Supplies pressurized fluid to the gear selector and service selector valves and accumulator
What is the hydraulic reservoir capacity?
.79 gal
What ensures the hydraulic reservoir remains pressurized in flight?
Nitrogen tank
What is normal hydraulic system pressure?
Up to 2875 psi
How is the system pressurized?
DC motor uses pressure switch to turn the motor on at less than 2450 psi and off between 2725 and 2875 psi
What will cause the hydraulic CAWS message to illuminate?
Less than 1800 psi
What is the function of the accumulator?
Maintain system pressure
Keep gear up if power package fails
What is the function of the nitrogen pressure cylinder?
Prevents pump cavitation
The nitrogen pressure cylinder is pressurized to what?
56 psi
Tires are inflated to what?
60 psi
What prevents gear retraction on the ground?
A de-energized solenoid plunger locks the landing gear handle in the down position
What is the minimum hydraulic fluid quantity needed for operation?
.66 gal
When might you get the hydraulic CAWS message on the ground after landing?
System cycled 6 times in an hour
What are two reasons you might receive a hydraulic CAWS message in flight?
Less than 1800 psi
System on for 10 minutes during flight
What keep the nose gear in the down position?
Drag link acts as an overcenter lock
What assists in lowering the nose gear during an emergency?
Spring strut…also holds drag link in over center position
What holds the main gear down?
Pawl lock mechanism holds the actuator in the fully extended position
What do red landing gear lights indicate?
In transit or unsafe condition
When would the gear horn sound and the gear lights illuminate?
Flaps >15 no gear down
A/S < 130 and throttle to idle
