11.13 landing gears Flashcards
what are the 3 main landing gear configurations
tail wheel, tricycle-type, tandem
where are the main landing gears usually located
around the centre of gravity
where is the tail wheel configuration mostly used
propeller, light aircraft
whats the most common landing gear configuration
tricycle configuration
whats the most uncommon landing gear configuration
tandem
where are fixed landing gears found
low speed, light aircrfat
whats the MLG
main landing gear
what does the trunnion link do on the MLG
connects the top of the leg to the wing structure, allows it to rotate
what 2 cylinders does a shock strut have
outer and inner
what do the upper and lower torsion links allow to extend
the strut
what does the side strut do
resist lateral or sideways movement
what does the gear down lock ensure
two parts cant fold together when extended
how does the down lock work
goes into an over centre position
whats the use of a shortening link
shortens the gear during retraction
whats the NLG
nose landing gear
on the NLG what does the torque link damper do
prevents wheel shimmy
what can existing shock absorbers be divided into
solid, oleo-pneumatic
what are main gear shock struts serviced wiht
nitrogen gas and hydraulic fluid
whats are the 3 positions of the LG control lever
up, off, down
when retracted what locks the gear in place
mechanical up-lock hook
in an emergency how will the landing gears be extended
an actuator will release the up-lock and the gears will free fall
what does the green indication mean in the cockpit
down and locked
what does the red indication mean in the cockpit
unlocked or traveling
what does no light indication mean in the cockpit
up and locked
how do microswitches operate
at very high speeds when in contact with an object
what are proximity switches at high risk of
dirt or moisture
what are the 2 types of proximity switch
reed, electronic
how can it be checked in the landing gear that its down and locked in the event of system failure
visual glass panels
what prevents the heat from the breaks damaging the tyres
heat shield
what temperature can the breaks reach
1000 degrees celcius
what bearings do wheels have
what are the 3 common aircraft brakes
single disc, dual disc, multiple disc
what energy converts to what when using the brake unit
kinetic to heat energy
where must you approach a tyre from if the brakes overheat
from the rolling direction
what aircraft use single disc brakes
small, light aircraft
what are the rotors and stators made of in the heat pack
carbon or steel
modern heat and brake pack assemblies have rotors and stators made from what
carbon fibre
carbon brakes last how much longer than steel brakes
20-50%
how much lighter are carbon heat packs then steel
40%
what is the brake piston housing made from
forged aluminium alloy
how do we look at the amount of break wear
wear indicator pin
how do we know when the heat pack is fully worn
the indicator pin is flush
how does the brake control/metering valve work
reacts to force on breaks
whats the function of brake deboosters
apply force over different sized pistons to reduce pressure
whats ABS
anti-lock braking system
what is maximum braking efficiency
wheels are decelerating at max rate but not skidding
what are control unit also known as in the anti skid system
brain
why must brakes not be applied immediately after touchdown
could cause a tyre blowout
what can the auto brake system do
stop the aircraft at selected deceleration without pilot input
when do auto brakes deactivate
the pilot presses the pedals
what are the different types of tyres
type I, type III, type VII, type VIII
describe type I tyres
design is no longer active, used on fixed gear aircraft
describe type III tyres
general aviation tyres, light aircraft
describe type VII tyres
high performance tyres, jet aircraft
describe type VIII tyres
high pressure and high speed, most advanced tyres on jets today
what is ply rating with tyres
relative strength
aircraft tyres can be classified as what 2 things
tubed or tubeless
what does radial ply allow for the tyres
high loads with minimal deformation
what 4 regions can tyres be split into
bead, carcass plies, tread, sidewall
what are beads in tyres
steel wires embedded in the rubber
what issue does the tread minimise in bad weather
hydroplaning
what are awl marks on tyres
green/grey paint marks to show where entrapped gasses where released in manufacture
what tyre thread is used on the nose wheel
chine tread
when inspecting tyres what would make it need replacing in terms with the tread
less than 2mm deep for more than 25% of the thread
how many times can an aircraft wheel be re-treaded before they are scrapped
10
how do dry braking flats occur
tyre locks while on dry surface
when does a wet braking flat occur
tyre locks while on wet surface
when must a tyre be removed in terms with inflation
when its less than 80% of the required psi
when can sidewall cracking occur
tyre experiences high deflection or weathering
how can braking damage the tyre
because of its high heat
where must tyres be store
cool, dry environment out of direct sunlight
what is differential breaking
operating the breaks on one side of the aircraft and not the other
whats is NWS
nose wheel steering
can torque links prevent nose wheel shimmy
not effective at it
how can shimmy be controlled on the nose wheel
damping
before a nose wheel retracts, because it is movable what must it do
self centre
what is used to self centre the nose wheel
centering cams
whats the purpose of the main gear steering
reduce tyre scrub and aircrafts turn radius
whats the max nose gear steering angle
70 degrees
whats the max MLG steering angle
5-8 degrees
what must the nose wheel steering be while towing
isolated/locked
what is air/ground sensing
prevent certain things happening in the air or ground
what is WOW
weight on wheels
where are WOW sensors located
main and nose gear shock struts
