11.13 Flashcards
(38 cards)
What are the 3 MLG arrangements used?
Tail wheel
Tricycle
Tandem
Characteristics of tail wheel configuration MLG
Used for light propeller a/c.
CG is behind main wheel
Has a skid/tail wheel.
Steering is done by braking or using rudder.
Characteristics of tricycle configuration MLG
Most common type.
CG is in front of MLG
Better forward vision than tail wheel.
Allows for more forceful application of brakes.
Characteristics of tandem configuration.
Relatively uncommon
CG is in between MLG
MLG is aligned along longitudinal axis.
Components of MLG
A shock strut
A side strut
A drag brace
Downlock/uplock assembly.
Trunnion
Actuator
Torsion link
Wheel and tyre assembly.
What does the trunnions link do
Connects the top of the leg to the wing structure and allows the leg to rotate into and out of the landing gear bay.
What do torsion links do on MLG
Allow the shock to extend, whilst maintaining its maximum while in the air.
What does aside strut do on MLG
Resists lateral or sideways movement.
What does drag strut do on MLG
Stabilises the leg in the longitudinal axis.
What is a shortening link on MLG
Used to maintain sufficient engine to surface clearance
Shortens the gear as they retract so they can fit into gear wells
Characteristics of nose landing gear.
Steerable
Two wheels
No brakes.
Lighter weight.
Not designed to take initial landing loads, can cause damage.
Retracts forward into fuselage.
What do nose wheels incorporate to align the wheel for retraction.
A centring cam
Why are torque link dampeners used
To prevent wheel shimmy
Wheel shimmy is the oscillating movements of the wheel left and right, caused by uneven tyre pressure or wear.
What two ways are the shock of landing absorbed.
Altered and transferred to the airframe at a slower rate.
Converted into heat.
What twoclssses of shock absorber are there?
Solid - a solid spring made of rubber or steel.
Oleo-pneumatic - a fluid spring with gas or oil, or a mixture of the two.
What is hydraulic diesel int
Occurs when air mixes with the hydraulic oil, forming small air bubbles.
When pressurised combustion occurs, instantly burning and cracking the rod or piston seals.
How does an oleo-pneumatic shock absorber work.
When the a/c lands, the fluid is pushed through a metering orifice and limits the speed of compression
Servicing of an oleo-pneumatic shock absorber
Serviced with nitrogen gas and the specified hydraulic fluid.
Wrong hydraulic fluid could cause deterioration of the oleo seals.
The extension length of the strut (X) and the air pressure can be measured.
During emergency extension of landing gear, are hydraulic doors open or closed
Open
Extension and retraction systems of landing gear.
Uses proximity switches and limit switches which input a computer which has a logic programme , this logic will direct other systems, and inform flight crew of necessary info.
Reed switch
Consists of two spring-loaded, normally open contacts.
The contacts are embedded in a glass tube which contains a gas to protect against corrosion.
The contacts are closed by a magnetic flux created by a permanent magnet moving adjacent to them.
The electrical circuit is closed
When are proximity switches used
Used instead of normal Microswitches where there is a high risk of contact corrosion due to dirt and moisture.
What are the two types if proximity switches
Reed switches
Electronic switches.
What are microswitches
A switch device that can open and close an electrical circuit at a very higher speed. Used when physical contact with an object is permissible.
