11.13 Landing Gear Flashcards
Which indication is given in most aircraft when the landing gear is all retracted and locked?
All landing gear lights are out
Which cockpit indication is normally given when the landing gear is all extended and locked?
A green light for each leg
When are the landing gear doors normally open?
During extension and retraction
When the landing gear free fall system is used, how are the landing gear doors closed?
They remain open
What typical systems can proximity switches be used with?
Flight controls and landing gear
What type of proximity switches are used in aircraft?
Reed and electric
What is a micro switch?
A switching device that can open and close circuits at high speeds
Jet aircraft use nose wheel landing and not tail, why?
- nose gear gives better directional stability
- prevents nosing over during break applications
The main landing gear retracts inboard into the fuselage, why?
Because only the fuselage has sufficient space for wheels
What are the characteristics of the nose landing gear on jet aircraft?
- has no breaks and extends with the air stream
- is steerable
Why are landing gear extension/ retraction systems needed?
To decrease drag therefore reducing fuel consumption
On commercial jet aircraft the wheel well doors are closed when?
At all times apart from extension and retraction
What is the main purpose of the shock strut?
- To support aircraft in the ground
- absorb shock on landing
The main function of the torsion links on the main gear is to?
Allow the inner cylinder to move yo and down in the outer cylinder but NOT to rotate.
What is the purpose of the torsion link damper?
Counteract wheel shimmy
What does the drag strut do?
Stabilises the shock
On most aircraft the main landing gear is kept in a retracted position during flight by what?
An up lock roller and an engaged up lock hook
When a shock strut is compressed the increase in pressure causes what?
The volume in gas to decrease
What is the function of the wiper ring?
Keep all unwanted material out of the shock strut whilst compression takes place
Where are dynamic seals used?
To seal the inner cylinder to the gland housing of areas with linear or rotational movement
Why do aircraft have nose wheel landing gear configuration?
Gives directional stability during take off and landing
On four wheel configuration the truck beam has a tilt mechanism to?
Bring the truck beam to certain position before retraction because wheel well has a restricted space
What is the tilt mechanism operated by?
A hydraulic truck positioning actuator
How do you set a mechanical parking brake in a Boeing aircraft?
Depress the break peddle then pull parking brake lever
What is the purpose of the anti- skid system?
Protects the tyres and gives more effective breaking
During breaking the main wheel speed is…?
Slower than the aircraft speed
During approach what does the anti- skid system do?
Sends full release signals to the anti skid valves
What is the function of the auto break system?
To stop the aircraft automatically
What force and support does the drag strut on a nose landing gear take?
- Takes longitudinal forces
- gives primary support for down/locked position
What does the rudder pedals steering interconnect mechanism connect together?
The rudder pedals to the nose wheel steering when the aircraft is on ground
Where is a lockstay found and what is the purpose?
It’s attached to the drag strut and controls alignment of folding strut
What do the three red lights of landing gear indicator mean?
That the gear is not locked
What is the purpose of the ramps on the main gear door?
Make sure the main door doesn’t interfere with gear during freefall extension
When gear down, pressure is appplied to open port of the door actuator and what else?
Lock port of the down lock actuator
After an alternate (emergency) landing gear extension, the landing gear doors….?
Remain open
To engage the operation of the landing gear control handle what must you do first?
Pull the handle out of the decent first
During breaking what happens to kinetic energy?
Kinetic energy is converted to heat energy
What are most aircraft wheels made from?
Aluminium alloy
Where is the inflating valve installed?
On the outboard half of the wheel
Where are the brakes installed?
On the inboard hand of the main gear wheels
What does the heat shield inside the wheel prevent?
The brake heat from damaging the wheels and tyres during normal braking
What is the purpose of the fuseable plug?
Automatically release tyre pressure at certain temperature levels
If the size of a tyre is 960 x 340 x 14, what does it mean?
- outside diameter = 960mm
- section width = 340mm
- rim diameter = 14 inches
Which types of tyre is used on a propeller aircraft?
Type 3
All aircraft brakes are what?
Disc brakes
What is the torque tube break connected to?
The stators
Which component changes hydraulic pressure to break force?
The pistons
If a break has 7 normal braking pistons how many overall pistons are ther?
14
7 for normal braking and 7 for alternate braking
The centre ribs are worn and shoulder ribs are still quite deep, what does this mean?
The tyre is over inflated
How often is the pressure checked?
Before each flight or each day
What are aircraft tyres inflated with?
Nitrogen
What does the heat pack in the brake discs consist of?
Steel or carbon rotors or stators
Which brakes can withstand higher temperatures?
Carbon brakes
Why do large heavy aircraft need power breaks?
Because the pilot cannot apply sufficient high brake pressure
What transmission is used between brake pedal and brake metering valve?
Cable or hydraulic transmission
What does differential braking mean?
- the left brake pedal controls the left brake
- the right brake pedal controls the right brake
What does the in flight braking system prevent?
Stops the wheel rotating during gear retraction
How many brake systems are required on large aircraft?
Minimum of 2 independent systems
What can the parking brake be supplied from?
The brake accumulator
What is the main function of the brake metering valve?
Regulate break pressure in proportion to brake pedal forces
The auto brake system regulates what?
A constant brake pressure
The anti skid system can only do what?
Decrease the brake hydraulic pressure
What does the up lock do?
Keep the gear retracted
How much can the rudder pedals steer the aircraft in degrees?
Max of 10 degrees each side
How much can the steering wheel steer the aircraft?
Up to 80 degrees left or right
How to release up lock mechanism?
Mechanical pull releases the up lock
Extend nose wheel?
Extend away from wind
