The Landing Gear Flashcards
Advantages of a tricycle gear
Better directional stability (CG further forward)
Less likely to nose over
Less drag improves takeoff performance.
Most common types of fixed landing gear
Spring Steel Leg / Cantilever
Rubber cord or bungee
Oleo Pneumatic Struts
Purpose of torque/torsion link
Stops plunger/sliding tube from rotating inside leg/body
Bogie Definition
Have at least for wheels per landing gear leg
Main disadvantage of bogie
When turning, crabbing will occur due to large footprint.
What acts as a damper (whole system)
The oil and nitrogen
What acts as a spring?
The gas acts as a spring to absorb the loads.
What acts as a damper?
The oil acts to dampen the spring action
Most likely cause of the fescalised portion of the leg being too small is:
Insufficient N2 pressure
Consequence of insufficient nitrogen gas in oleo strut?
Bottoming-out on landing
Ramifications of insufficient oil
Gear rebound is not properly damped
Purpose of mechanical lock?
Prevents creep.
Break Bars
Torque limiting devices that limits force through brakes, then through the wheels.
Nose Wheel Requirements
Free Castoring, to allow differential braking
Automatic self centering to ensure nosewheel is centered prior to retraction.
Shimmy Protection
Which additional load may nosewheel steering cause on the landing gear?
Towing - Shear
Define Castoring
The ability of the nosewheel to move either side of the neutral position.
Ground Locks
Must be removed before flight.
What prevents the inadvertent retraction of the landing gear on the ground?
A solenoid operated LATCH pin
Emergency Gear Extension
Via Gravity, however doors will be too big to close. Therefore the protruding material is frangible, and will be replaced.
Amber Lights - Indication
Amber lights are for DOOR INDICATION.
Scenario - no landing gear main lights, however 1 is amber. What is a possible scenario?
Undercarriage is up and locked. Landing gear doors are party open/not fully closed.
Continuous L/G Horn
Will sound if in landing configuration, throttles are set to less than 33%, will continue until L/G is down and locked.
Red Landing Gear Indication
Gear is unlocked
VLE
Maximum Speed with Landing Gear Extended
VLO
Maximum Landing Gear Operating Speed - Undercarriage doors limiting factor, slowest of the landing gear speeds.
What does a tiller operate?
Small electric / hydraulic motor connected to nosewheel strut.
Nosewheel Shimmy
Rapid, sinusoidal oscillation of the nosewheel, divergent in nature.
Caushes of Shimmy
Uneven tyre pressures
Uneven worn tyres
Unbalanced wheels
Worn shimmy damper
Worn torque link
Reduction of shimmy
Hydraulic jack across steering jack piston
Hydraulic damper
Double nosewheels
Maarstrand Tyres
Twin contact tyres
What is the purpose of a loose/detachable flange
Designed to facilitate tyre replacement
Define Tyre Creep
Tendency of the tyre to rotate around the circumference of the wheel.
Purpose of Fusible Plugs
Prevent the tyre against explosion due to excessive temperature.
How many Fusible Plugs are there, and where are they fitted?
One or more, on inner half of the wheel
