Construction and operation Flashcards
Outline Gear retraction
Gear retraction is done by placing the selector into the “gear up” position.
A HYD pump forces fluid into the gear retraction side of the cylinder releasing the down-lock and raising the gear.
Sequence valves are used to ensure the wheel well doors are opened before gear is actuated
A pressure switch stops the HYD pump at a predetermined pressure once the gear is raised and locked.
Define a screw jack
type of jack that is operated by turning a leadscrew.
used to lift moderately and heavy weights
used to raise/lower landing gear
Define an Actuator
An actuator is a component that is responsible for moving and controlling a mechanism
the bit that actually does the moving
What is an Oleo
An air-oil shock absorber
made of a piston inside a cylinder full of HYD fluid charged with nitrogen for shock absorbtion
what types of Oleo are there
With seperator
without separator
What is the purpose of suspension and what are the two methods
Direct action and articulated
absorb and dissipate the kinetic energy of landing impact, thereby reducing the impact loads transmitted to the airframe.
What is direct action suspension
The oleo is inline with the wheel and moves up and down
What is articulated suspension
The oleo moves up and down but the wheel moves back
What is the purpose of linkages and what are the two types
to provide independent suspension
Scissor link and drag link
What are the two types of wheel ASSY
Divided and loose flange
What is the difference between loose flange and divided wheel ASSY
A divided wheel is held together by bolts in two halves
a loose flange means that the flange can be removed (has an O ring)
What are fusible plugs
Used to safely deflate tyres due to over heating.
Located in aircraft main wheels.
Colour coded (Red / Green / Yellow) to
indicate maximum heat loading.
Fitted in groups of three (3)
What are Drive blocks
Used to attach the brakes to the wheels
What are Balance weights
Washers used to balance the wheel
What are valve stems
The tyre inflation valve (Schrader type)
Outline Gear extension
Gear extension is done by placing the selector into the “gear down” position.
Fluid is released on the up side of the cylinders, flowing through the power pack and allowing the gear to free fall
A restrictor in the form of a check valve prevents the wheel from falling so fast it could damage the structure under its own weight.
The wheels lock into the downlock position
what are the two methods of shock strut suspension
direct action
fully articulated
what is a scissor link
limits oleo extension and keeps wheels in alignment
what is a drag link
prevents over travel of landing gear during extension
