Landing Gear (Sensei) Flashcards
are in the area of the aircraft’s center of gravity.
main gears
can be a nose wheel or a tail wheel.
supporting gear
On aircraft with nose wheel landing gear, the center of gravity is
in front of the main wheels.
Landing gear _____ permits more forceful application of brakes on landing.
with a nose wheel
landing gear on _____is retracted during flight.
modern jet aircraft
Non-retractable landing gear is used on slow flying which is
piston engine aircraft.
which statement is true?
-The wing gears are mounted on the wings.
-The body gears are mounted on the aircraft body.
-The centerline gear is fitted to the fuselage.
The nose landing gear on jet aircraft has _______
It is steerable and it has no brakes.
two wheels.
is lighter than the main gears because it carries less load.
and its supporting structure is not designed to support initial landing loads.
nose gear
Aircraft steering is controlled from the cockpit by the?
rudder pedals
are used to steer the aircraft at low speeds or around narrow bends.
steering wheels
there is a direct mechanical connection between the rudder pedals and the nose gear.
direct nose wheel steering systems
transmits signals from the rudder pedals or the steering wheel via cables or via electric wires to a steering control valve.
indirect steering system
supplies hydraulic pressure to the pistons in the steering cylinders and this moves the nose wheels in the commanded direction.
steering control valve
During flight the landing gear is retracted and the landing gear doors are?
closed
are classified into nose landing gear doors and main landing gear doors.
Landing gear doors
controls the extension and retraction of the landing gear.
landing gear lever
is used if the normal system does not operate, for example if hydraulic power is not available. This system is controlled from the cockpit. It uses mechanical and electrical components to release the gear.
alternate system
supports the aircraft on the ground and protects the aircraft structure by absorbing the shock on landing.
uses compressed nitrogen and hydraulic fluid to absorb the shocks.
has two telescopic cylinders - an outer cylinder and an inner cylinder.
shock strut
works like a spring to absorb the shock and the hydraulic fluid has a dampening function
compressed nitrogen gas
is a single piece of high strength, heat treated steel forging it is designed to fit the inner cylinder.
outer cylinder
is mounted between the shock strut and the wing area.
transmits the landing gear shock loads from the drag strut to the aircraft structure.
has forward and aft hinge points for main gear retraction.
trunnion link
is usually mounted in the wing area and the aft bearing is usually mounted in a support beam or rib.
forward bearing
Grease nipples are used for?
lubrication
can transmit vertical loads and drag loads into the airframe without transferring torque to the structure and to the outer cylinder during structural deflections.
spherical bearing
is designed to slide into the outer cylinder.
inner cylinder
permit the inner cylinder to move up and down in the outer cylinder, but do not permit the inner cylinder to rotate in the outer cylinder.
has two sections - an upper torsion link which is connected to the outer cylinder and a lower torsion link which is connected to the inner cylinder.
torsion links
is sometimes named the shimmy damper because it is used to counteract wheel shimmy.
torsion link damper
is the rapid oscillation of the wheel to the left and the right of the direction of travel. It is caused by uneven tire pressure, uneven tire wear or uneven runway surface.
Wheel shimmy
stabilizes the shock strut in the fore and aft direction during take off, landing and taxing.
drag strut stabilizes the shock strut in the fore and aft directions and locks the nose gear in the down and up positions.
drag strut
gives lateral support to the shock strut.
side strut
makes sure that the two parts cannot fold together when the main gear is extended.
gear downlock mechanism
converts hydraulic pressure into mechanical energy to extend and retract the main gear.
main gear actuator
devices control the speed at which the actuator cylinder operates.
restrict the flow toward the end of the extension or the retraction.
make sure that the gears lock in the extended or retracted position without shocks.
fluid metering
makes sure that the gear is in the down and locked position.
On some aircraft it is named the lock stay or the jury strut.
is kept in the overcentered down and locked position by the downlock springs.
lock strut
are mounted on the lock strut. It sense when the gear is in the down and locked position.
Downlock sensors
unlocks the lock strut against the force of the downlock springs when the gear is being retracted and locks the lock strut in the down and locked position when the gear is extended.
downlock actuator
may be used to lock the downlock actuator when the aircraft is on the ground. It blocks the downlock actuator rod.
Ground safety locks, or sleeves
is hydraulically operated. If the hydraulic system malfunctions, the uplock can be operated by alternate electrical or mechanical systems.
uplock mechanism
is engaged when the gear is retracted. This makes sure that the main gear is up and locked during flight. Is kept in the overcentered engaged position by the uplock spring.
uplock hook
are serviced with nitrogen gas and with specified hydraulic fluid.
Main gear shock struts
is a tubular steel beam. It has single-piece axles at each end to support the four wheels.
are tilted by a tilt mechanism. On some aircraft the tilt mechanism is named the bogie alignment pitch trimmer.
truck beam
is supplied by one of the hydraulic systems.
truck positioning actuator
provides directional control of the aircraft during take-off and taxiing.
body gear steering system
has a hinge for body gear retraction.
guides landing loads into the fuselage.
body gear trunnion
gives heavy aircraft a larger foot print.
centerline gear
is a two stage oleo-pneumatic unit. It includes the sliding tube and it is installed on the main fitting.
consists of the sliding tube and the plunger tube. It is filled with hydraulic fluid and nitrogen through a servicing valve at the upper part of the plunger tube.
has two centering cams - an upper centering cam and a lower centering cam.
shock absorber
is attached to the drag strut assembly. The lockstay gives secondary support for the down and locked position of the nose gear. It controls the alignment of the folding drag strut.
lockstay
which statement is true?
The upper link is made of forged aluminurn.It is connected by lugs to the top of the shock strut outer cylinder and to the downlock actuator.
The lower link is made of steel. The lower link is connected to the forestay of the drag strut assembly.
means that the pivot point centers are not in a straight line.
Overcentered
can be inserted in a ground lock pin hole between the upper link and the lower link.
locking pin
converts hydraulic pressure into mechanical energy to extend or retract the nose gear.
nose gear actuator
is the main supporting member of the nose gear.
nose gear shock strut
engage when the inner cylinder extends to make sure that the nose gear is in a straight and forward position during retraction.
centering cams
is a freely rotatable toothed tube. It is located between the shock strut and the sliding tube and turned by the steering actuating cylinder.
rotating tube
is connected to the nose gear proximity detector assembly. The detector monitors the shock absorber and wheel position.
upper torque link
is at the upper part of the shock absorber between the plunger tube and the sliding tube
is not subjected to heavy side loads in this location.
dynamic seal
slides between the plunger tube and the rotating tube.
has a metering tube for oil transfer.
sliding tube
are attached to the lower torque link at the lower part of the sliding tube.
are designed to shear if the towing load is more than the limit. This decreases the risk of damage to the sliding tube.
Towing lugs
use hydraulically powered indirect steering systems, which are also called follow up systems
Jet aircraft
is mechanically operated and hydraulically actuated.
system 1
is electrically operated and hydraulically actuated.
system 2
are transmitted via potentiometers to the brake and steering control unit.
can achieve greater steering angles
Steering orders from the handwheels
receives electrical signals from the brake and steering control unit and sends hydraulic pressure signals to the steering actuating cylinders.
an electrically operated selector valve and a servo valve.
hydraulic block
is used on some aircraft to protect the tires from damage due to scrubbing when the main gears resist the turn.
Main gear steering
which statement is true?
These doors are hinged to the aircraft structure and operated hydraulically via linkages and an actuating cylinder.
The aft nose gear doors are symmetrical about the center line of the aircraft and hinged to the aircraft structure.
is attached to the back of the nose gear leg. It opens and closes with the extension and retraction of the nose gear
leg door
are attached to the fuselage structure by hinges and operated by hydraulic actuating cylinders.
main doors
on the main doors make sure that the doors do not interfere with the gear during free fall extension.
ramps
are used to detect the position of the main doors.
monitor the compression of the landing gear shock struts on the movement of the torsion link.
Proximity sensors
can be released during maintenance by a ground control handle which is connected to the manual unlock crank, or by the application of hydraulic pressure.
mechanical lock
is hinged to the wing skin and connected to the landing gear by an adjustable rod.
hinged fairing
is attached to the shock strut by studs and rods.
fixed fairing
controls the landing gear under normal conditions.
landing gear control lever
Landing gear position indications are necessary on aircraft with
retractable landing gears.
which statement is true?
The standby unit becomes active if the other unit fails or after each landing gear cycle. In this case the active unit changes to standby.
The active landing gear control unit sends control signals to the selector valves and again the selector valves control the extension and retraction of the gears and movement of the doors.
The landing gear position feedback signals cancel the control signal when the gear reaches the commanded position.
landing gear lever cannot be moved to the up position when the aircraft is?
On the ground
allows you to select the UP position of the control lever at any time - even when the aircraft is on the ground. This means the landing gear retracts if the hydraulic system is activated.
lock override
control the position indication lights.
receive information about the lever position from
landing gear control units
provides the power to extend and retract the wing gears.
gear actuator
controls the flow of hydraulic fluid to the gear actuator, the uplock actuator and the downlock actuator. This valve makes sure that the gears can begin to extend or retract only after the gear doors are fully open. The valve is operated mechanically by the wing gear door rod.
door operated gear sequence valve
controls hydraulic pressure to the open side of the door actuator. This valve allows pressure to the open side of the door actuator during gear extension and removes the pressure from the open side when the gear is down and locked. This valve is operated by the gear hook in the uplock mechanism.
downlock operated door sequence valve
hydraulically connected to the downlock operated door sequence valve. It also controls hydraulic pressure to the close side of the door actuator.
uplock operated sequence valve
is installed in the door close hydraulic line from the door actuator to the uplock operated door sequence valve. The door safety valve blocks the pressure to the close port of the door actuator and connects the close port with the return line.
wing gear door safety valve
receives signals about the position of the doors and the gears from proximity sensors and sends a command signal to the selector valve manifold.
landing gear control and interface unit, or L.G.C.I.U. for short.
which statement is true?
solenoid controlled safety valve blocks the hydraulic supply to the landing gear at high airspeeds.
door bypass valve allows the main gear doors to be opened when the aircraft is on the ground
is controlled by the alternate extension handle on the center pedestal in the cockpit.
free fall system
1.) The shock absorber on ground the target is ___
2.) The shock absorber in flight the target is ____
1.) FAR from the sensor.
2.) NEAR to the sensor.
are used instead of normal micro switches where there is a high risk of contact corrosion due to dirt and moisture.
are used mainly for position sensing in areas outside the pressurized fuselage
Proximity switches
consists of two spring loaded, normally open, contacts.
Reed switch
contains a sensing coil which is electrically excited by an electronic unit.
electronic type proximity switch
The life span of a tire is calculated on the number of?
take-offs and landings.
A tire can be used for approximately _______landings and take-offs.
150
______use single disk brakes but
______ use multi disk brakes.
1.)Small aircraft
2.) jet aircraft
The pilot can also slow down the aircraft by using aerodynamic drag from the flaps and slats and the auto spoilers and by using the
thrust reversers
prevents the brake heat from damaging the wheels and tires during normal braking.
heat shield
automatically release the tire pressure when the temperature of the wheel Increases to a certain level.
Fusible plugs
have a pressure indicator which can be read directly or a pressure sensor which sends information to the tire pressure indicating system.
Tire inflating valves
is the maximum speed capability of the tire and the load rating is the maximum load carrying capability of the tire
speed rating
which statement is true?
Type 3 tires are low pressure tires. They are used on propeller powered aircraft with ground speeds of less than 160 miles per hour. These tires have a greater section width in relation to rim diameter than other tires. This gives lower pressures and improved cushioning and flotation.
Type 7 tires are very high pressure tires.
They can carry very big loads. They are the standard tires used on jet aircraft with ground speeds up to 225 miles per hour.
Type 8 tires are extra high pressure tires with a speed rating of 280 miles per hour. They are used on military aircraft and on some very heavy freighter aircraft.
Type 7 tires are low pressure tires. They are used on propeller powered aircraft with ground speeds of less than 160 miles per hour. These tires have a greater section width in relation to rim diameter than other tires. This gives lower pressures and improved cushioning and flotation.
aircraft tires must be?
permanently marked
is an index of its strength. When tire plies were made of cotton the rating was the same as the number of plies.
ply rating
is the wearing surface on the outer circumference of the tire. It is made of a rubber which is specially compounded for toughness and durability.
tread
has a pattern or grooves molded into its surface.
This gives good traction under different
rib tread
in the tread minimizes the problem of hydroplaning
right pattern
how many times that the aircraft cen be retreaded before they are scraped?
10 times
is a layer of flexible, weather resistant rubber which protects the carcass. The sidewall extends from the tread to the bead area.
sidewall
is a layer of specially compounded rubber which is placed over the carcass.
gives good adhesion between the tread and the carcass.
undertread
is one or more layers of nylon fabric. The tread reinforcement counters the centrifugal forces which try to pull the tread from the carcass during high speed operation.
tread reinforcement
is a 3 millimeter layer of low permeability rubber on the inside of a tubeless tire. All jet aircraft tires are tubeless.
is like a built in tube. It minimizes the amount of gas that seeps out into the carcass plies. But some gas does seep though the inner liner.
inner liner
allow this gas out into the atmosphere and prevent ply separation.
are located in the lower sidewall. They are usually marked green or yellow.
vent holes
is a red dot on the sidewall. It marks the lightest part of the tire.
The red dot is positioned adjacent to the inflation valve during wheel assembly.
balance mark
are a composite of rubber and steel.
They are concentrated in the area under the tread.
give the tires strength in the tread area
belt plies
is a good isolator so the heat that is generated in a tire is dissipated slowly. Tires need time to cool down before they are used again.
Rubber
A _______tire has a deflection of 32 percent when loaded. This gives good tread wear.
properly inflated
if the tire is ______the deflection is less than 32 percent. This causes excessive wear to the center tread.
over inflated
If the tire is ______ the deflection is more than 32 percent
under inflated
It causes excessive stress, ply separation and a weakening of the carcass
Under Inflation
brakes are used on small general aviation aircraft.
Single disc
It is similar to the single disc brake except that two rotating discs are used instead of one.
is used when more friction is required.
dual disc brake.
are used on large jet aircraft.
They are designed for use with power control brake systems.
Multiple disc brakes
the torque of the stator discs to the piston housing.
This is done by splines. It is usually made of forged steel. It has a back plate.
torque tube transmits
consists of alternate rotors and stators. They are made of carbon or steel.
heat pack
they are lighter - about one third the weight, have less wear than steel heat packages and they can withstand much higher temperatures.
advantage of carbon heat packs over steel heat packs
they are more expensive to produce than steel heat packs. However the discs can be recycled. In general one new carbon disc can be made from two used discs.
disadvantage of carbon heat packs
is fed into the base of the furnace. This gas consists of one carbon atom and four hydrogen atoms.
Methane gas
gives a visual indication of the overall wear of the heat pack.
wear indicator pin
in general 1mm of wear pin length corresponds to between 20 and 30 landings.
Before checking the brake wear the parking brake must be set, the brake must be cold and the wear indicator pin must be within limits.
TRUE
is used on all large aircraft. With power braking the brake pedals do not operate the brakes directly.
Power braking
This means that the brakes on the left main gear wheels and the brakes on the right main gear wheels can be operated separately.
differential braking.
is supplied by hydraulic system 2. It is always operated together with the normal brake metering valve.
reserve braking system
to protect the tires and to provide more efficient braking.
can detect and correct a skidding condition much faster than the pilot can via the pedals
are designed to give optimum braking effectiveness when the brake pedals are fully applied.
anti-skid system
send an anti-skid signal to the anti-skid valve.
anti-skid control circuits
can stop the aircraft at the selected deceleration level without the pilots touching the brake pedals.
reduces the delay between touchdown and brake application.
automatically applies the brakes after automatic speed brake extension at touchdown.
auto brake system
The ____stage shows a smooth build up of brake pressure until the preselected deceleration rate is reached
on ramp’
The _______stage shows a smooth decrease in brake pressure
is initiated when the speed brakes are retracted or if the pilot uses the brake pedals during the landing roll.
‘off ramp’
