Landing Gear / Oxygen / Pneumatics Flashcards
Where is the ‘Wheel Base’ measured from?
From the centre of the boogie beam from NLG to MLG
Where is the ‘Wheel Track’ measured from?
From the centre of the boogie beam from left to right main landing gear
During landing kinetic energy is transferred into?
Heat energy
When 4-6 wheels are connected to a landing gear they are connected to?
Boogie beams and gear trucks
What is the function of the fluid inside the strut?
Slows down the strut movement during the extension od the shock absorber
In what part of the gear would you find fluid and nitrogen?
In the strut combined within the shock absorber
What other sub-systems are in the landing gear system?
- The brake system
- The NWS system
- The flight/ground switching system
Is it possible to move the landing gear handle on the ground?
yes
How does the emergency landing gear extension system work?
From a handle in the flight deck the gear can be manually unlocked via control cables. Gravity allows the gear to fall and bungee springs hold it in the locked position.
What is the purpose of the brake control valve?
The brake control valves control the pressure on the brakes and make sure there is sufficient braking force.
For what purpose are flow limiter or fuses responsible in a brake system?
They are used to prevent all brakes from becoming powerless if one of the brakes or brake lines leak. They will shut off further pressure so not all pressure is lost.
What is the function of the anti-skid system?
The anti-skid measures the deceleration of the wheels, if the wheels de-accelerate too much then the brake pressure will decrease.
Explain how a parking brake works on a typical airliner?
It is done either by pressing pedals all the way down with the help of the parking brake leaver or electrically by opening a valve supporting hyd pressure direct to the brakes.
What does shimmy mean?
the undesirable unsteadiness of the gears.
What is used to prevent shimmy?
A spring operated accumulator is installed between the torque link assembly.
What is the purpose of a ground shift mechanism?
It is a mechanical system to indicate when the aircraft is on the ground or the gear is under pressure
What kind of wheel rims are used on an aircraft?
Aluminium alloy rims in the split hub style with an o-ring between to prevent nitrogen leakages.
What is meant by re-treading?
Method of restoring a used retreadable tire by renewing the tread alone or by renewing the tread plus the reinforcing ply
Where does the centre of gravity lie when the aircraft is on the ground?
Always between the landing gears
What is being developed to keep the pressure on the runway as low as possible?
Landing gears are being developed with more and more wheels.
Down lock springs are also called?
Bungee Springs
What will a brake adjuster do?
Adjust the brakes according to wear
What is the advantage of carbon brakes?
They have a constant output whether hot or cold and are not susceptible to thermal shock
What is installed to move the rotor vanes of brakes when the wheels are turning?
Splines
What mechanism locks the gear when extended?
Over centre links
What should be used when inflating a newly fitted tyre?
A safety cage
What are the two types of tyres?
Radial and Bias
What type of bearings are used in aircraft wheels?
Conical roller bearings
What does the amber light on a landing gear panel indicate?
Wheel well doors are not closed
What does a light out on the Landing Gear panel mean?
Gear and doors are up and locked closed
What does a green light on the Landing Gear panel in the flight deck indicate?
Landing gear is down and locked
A valve that allows the Gear Up or Gear Down movement to happen in the right order is?
Sequence Valve
When is the nose wheel steerable?
When the nose gear shock absorber is compressed (on the ground)
What is the pressure called inside a strut?
Pre-Charge
What is the percentage of oxygen in the air?
21%
What is the normal way to prevent hypoxia in an aircraft?
Pressurise the cabin
Chemical oxygen generator systems are normally provided for?
Passengers in failure of the pressurisation system or insufficient cabin air flow
What is the function of the LP supply valve in the crew oxygen system?
To allow of shut off the oxygen control to the distribution manifold
How is the crew oxygen cylinder protected from over pressure?
By a rupturing pressure relief valve that releases oxygen overboard through a discharge line
The amount of time during which a pilot is able to effectivley or adiquatly fly is aircraft with insufficient oxygen is?
Effective Time Performance
Oxygen cylinders can be made from?
Steel, Aluminium or Composites
What is the purpose of the crew oxygen pressure regulator?
To step the bottle pressure down from 2200 PSI to around 20-75 PSI
The cabin altitude at which masks will be automatically released is?
14000 Feet
What is the purpose of a pneumatic isolation valve?
To split OR connect different pneumatic systems
Which component is responsible for pneumatic temperature control?
Fan Air Valve - this supplies cool engine air.
Where is air taken from to cool the pneumatic air in the heat exchanger?
Fan Cooled Air
The over pressure valve protects the users if air is provided from?
The engine HP or LP compressor stage.
What is the purpose of the HP control valve?
It is used to determine the source of engine compressor stage
Why is important to energise the aircraft prior to pressurising a pneumatic system from external?
Pneumatic systems may start unwanted or unprotected
What are pneumatic sources in flight?
Engine and APU
Pneumatic operated systems should not be supplied with cold pneumatic air from external, why?
Otherwise icing of valves or turbines may occur
In what ways can pneumatic leak detection be carried out?
- Thermal Switches
- Manifold failure loops
- Pressure switches.
