Landing Gear Flashcards
Describe the landing gear.
Fully retractable, hydraulically operated
Describe the struts.
They are air oil assemblies
What is the actuator fitted to?
One actuator is fitted to each landing gear assembly.
How is hydraulic pressure provided?
Provided by electrically powered hydraulic pump. Activated by pressure switch when required pressure is too low.
How is pressure maintained in the landing gear?
Accumulator maintains pressure whilst actuators operating - prevents starting and stopping of pump
How is pressure required for landing gear movement?
Electrically operated hydraulic valves operated by gear selector provide required amount of pressure.
How long does gear extension take?
6-10secs
How does the landing gear stay retracted?
Hydraulic pressure on both sides of actuators - larger surface on retract side.
What does the accumulator do?
The accumulator acts as a pressurised gas container so it keeps pressure constant by replacing volume lost due to normal leakages.
What is the purpose of the accumulator?
Replacing the lost volume prevents starting hydraulic pump in flight.
What prevents gear retraction on the ground?
Electric squat switch prevents hydraulic valve from switching if the master On and gear switch in Up.
What ensures gear extension and locking the gear down?
Springs assist the hydraulic system in extension and locking the gear down.
Extended with 3 hydraulic cylinders
Keeping the landing gear locked down.
Hydraulic pressure supplied to 3 actuators
Downlock hooks engage - springs maintain force on each hook until released by hydraulic pressure.
What happens when normal gear extension fails?
Emergency gear extension lever releases hydraulic pressure -> hydraulic fluid can pass through emergency extension valve.
-> Gravity allows for extension in the event of a failure.
What is the visible strut on the main gear?
4cm
