AGK Systems - Landing Gear Flashcards
Landing gear loads.
Torsion loads absorbed by torsion link.
Main gear absorbs vertical load and transfers it through the oil and into the torsion box, wing spars and keel beam.
What gas is the emergency deploy for gear?
Nitrogen.
What are bogies and trucks?
Bogies - at least four wheels per landing gear leg.
Sets of wheels mounted onto bogie beam attached to leg either as a bogie or truck.
What % of the impact is absorbed by the shock absorbers?
90%.
Oleo strut uses compressed nitrogen and oil, gas acts as a spring to absorb the loads, oil acts to dampen the spring action.
What is the oleo strut?
Rate at which the strut can compress is limited by the speed the oil can flow through the damper orifice.
Normally contains hydraulic oil(DTD 585) and nitrogen.
Uses gas pressure to support the aircrafts weight and act as a spring to absorb.
Uses oil to control rate of compression and extension or recoil.
Nose landing gear image.
Image in files, 1, learn.
How is landing gear extended/retracted?
Controlled by selector valves and sequence valves, which sequence the open and closing of the gear doors.
As well as the control of down locks and uplocks.
Active hydraulic system, engine pump.
What are down locks?
Ensure accidental retraction cannot happen.
Geometric/over centre locks used to lock gear down.
Doesn’t require hydraulic power.
Needs a mechanical means to break lock prior to leg retracting.
What are up locks?
Type of hook lock which requires hydraulic pressure.
What are micro and proximity switches?
Proximity - detect ferrous metal in close proximity.
Micro - require actuation with contact pad in the gear, used for weight on wheel switch.
What are the forces during a turn?
Torsional force, greatest force felt between the inner and outer section of oleo strut.
Force felt upwards through oleo strut.
Landing gear operating speed.
VLO - Velocity landing gear operating (travelling, doors open)
VLE - Velocity landing gear extended (down, door closed)
Emergency gear extension.
Manual system - hand crank.
Compressed nitrogen.
Gravity.
What is retraction centrering?
Nose wheel must be correctly aligned.
Two cams fitted to the cylinder of the leg, cams align and centre the nose prior to retracting.
Steer-to-centre switches drive a hydraulic motor to centre the wheels.
What is a nose wheel shimmy?
How do you prevent it?
Uncontrolled vibration of wheel assembly around legs axis of rotation.
Caused by: faulty torque links, wear in wheel bearings, inadequate tyre pressure.
