11.13

Question 1

Whats the three configuration for main landing gear ?

Answer 1

Tail wheel
Tricycle - type
Tandem

Question 2

Explain a tail wheel configuration ?

Answer 2

Main gear is located forward of the Centre of gravity.

Question 3

Explain tricycle configuration ?

Answer 3

Centre of gravity is positioned ahead of main landing gear.

Question 4

Whats 3 advantages for a main landing gear tricycle configuration ?

Answer 4

-Provides stability

-Allows more forceful application of the brakes without nosing over.

-Forward vision isn’t obstructed

Question 5

Explain tandem landing gear configuration ?

Answer 5

Landing gear is installed back to back on the longitudinal axis

Landing gear is positioned forward and aft the centre of gravity

( glider plane )

Question 6

What does a Main landing gear assembly consist of ?

Answer 6

Shock strut
Side strut
Drag brace
Downlock assembly
Uplock assembly
Trunnion
Actuator
Torsion link
Wheel and tyre

Question 7

What does the trunnion link connect ?

Answer 7

Top of leg to the wing structure
( allows leg to rotate into and out of the landing gear )

Question 8

Whats the two telescopic cylinders a shock strut has ?

Answer 8

Outer cylinder
Inner cylinder

Question 9

What is has each cylinder filled with ?

Answer 9

Hydraulic oil and nitrogen

Question 10

What does the torsion link connect ?

Answer 10

Connect the inner moving cylinder of shock strut to fixed outer cylinder.

Question 11

What does the side strut resist ?

Answer 11

Sideways movement
( connected to upper side of aircraft structure and on the other side, via a joint to the shock strut )

Question 12

Whats the drag struts function on the landing gear ?

Answer 12

Provides longitudinal support

Question 13

Whats the function of a gear down-lock mechanism ?

Answer 13

Ensures gear doesn’t fold when extended

Question 14

When are the locating cams not engaged on the nose landing gear ?

Answer 14

When the weight of the aircraft is on the wheels.
( engagement of cam ensures wheels are at 90 degrees )

Question 15

What does a steering actuator do ?

Answer 15

Rotates nose landing gears inner cylinder which turns the wheel

Question 16

What controls the impact force n an aircraft during landing ?

Answer 16

Shock absorber

Question 17

Whats the two main classes of shock absorbers ?

Answer 17

Solid

Oleo

Question 18

How does a solid shock absorber absorb the landing impact ?

Answer 18

Via a spring made from steel

Question 19

How does an oleo shock absorber absorb the landing impact ?

Answer 19

Using Fluid spring with gas or oil, or mixture of two

Question 20

How are the gas chambers and oil chamber separated ?

Answer 20

By a piston
( this type of separated oleo is called a - Oleo-pneumatic strut with separator )

Question 21

Whats the two types of oleo?

Answer 21

Oleo with separator
Oleo without separator

Question 22

Whats the two principles that allow a shock absorber to transfer the landing impact to the fuselage ?

Answer 22

Converting energy into heat energy

Transferring throughout airframe at different rates than the single strong pulse of impact.

Question 23

Whats the purpose of the restricter valve in the outer cylinder on an aircraft’s landing gear ?

Answer 23

Compresses the gas which doesn’t allow the inner cylinder to suddenly move up into the outer cylinder, instead it slows the movement down. This is done by the use of a flutter plate

Question 24

What gas are main gear shock strut serviced with ?

Answer 24

Nitrogen gas

Question 25

What should be done for shock strut servicing ?

Answer 25

Strut dimension X and gas pressure is measured.

Question 26

When the landing gear lever is placed to off after retraction, what does this do ?

Answer 26

Depressurised system and cuts off hydraulic pressure supply.

Question 27

During gravity extension of the gear, do the doors close ?

Answer 27

No. They stay open.

Question 28

how does the gravity extension gear fall in a controlled speed and doesn’t swing violently down ?

Answer 28

Due to selector valves in the hydraulic system connecting the pressure and return lines.

Question 29

If the landing gear warning indicators fail, Whats an alternative way of checking for full extension and locking ?

Answer 29

Gear down lock viewers ( located in the floor under access panel and you must check for red alignment marks which means thy have locked )

Question 30

Whats two landing gear positions indication systems ?

Answer 30

Indicator lights near gear lever ECAM ( airbus ) or EICAS ( Boeing ) -these position doors and gear

Question 31

What is a Microswitch’s function on the landing gear ?

Answer 31

Connected from lever to the gear position sensor and determines weather they both show the correct position ( red indication light illuminated shows that there is a disagreement between the control lever position and position of the landing gear/ door )

Question 32

Whats a micro switch ?

Answer 32

Device which opens and closes an electrical circuit.

Question 33

Whats a proximity switch ?

Answer 33

Used over micro switch where there is a high chance of contact corrosion due to dirt etc

Question 34

Whats the 2 types of proximity switches ?

Answer 34

Reed switch Electronic switch

Question 35

What does a proximity switch consist of ?

Answer 35

Target Sensor

Question 36

Explain the operation of a reed switch ?

Answer 36

Consists of 2 spring loaded contacts in glass tube Contacts are closed by magnetic flux Electric circuit is closed and operates switching function

Question 37

Explain does a electronic proximity switch consist of ?

Answer 37

Consist of sensing coil and non-magnetic target

Question 38

How is the wheel supported ?

Answer 38

On axial by a tapered bearing.

Question 39

What are aircraft wheels usually made from ?

Answer 39

Aluminium and magnesium alloy

Question 40

What attaches the inboard half and outboard half together ?

Answer 40

Tie bolts

Question 41

What absorbs the heat cause from the brakes on a wheel ?

Answer 41

Heat Shield found in between outboard and inboard half of the wheel ?

Question 42

What happens if the heat shield experiences a harsh braking force which generates a lot of heat ?

Answer 42

It can’t take the heat so its uncontrollably distributed to wheel which can cause tyre to burst

Question 43

Where is the inflation valve located ?

Answer 43

Outboard half

Question 44

Whats found at the inboard half of the wheel ?

Answer 44

Heat shield Brake unit Fuse plug

Question 45

Whats the 3 types of aircraft brakes ?

Answer 45

Single disc Dual disc Multiple disc

Question 46

How are single disc brakes engaged ?

Answer 46

Friction between both sides of a calliper

Question 47

When are dual discs used ?

Answer 47

When the aircraft requires more braking force

Question 48

Whats located between the two discs ?

Answer 48

Centre carrier

Question 49

What do stators and rotors provide on a multiple disc ?

Answer 49

Provide friction surfaces for braking effect ( burning braking, stators and rotors are squeezed together between pressure plate )

Question 50

How much longer do carbon brakes last then steel brakes ?

Answer 50

20-50 %

Question 51

Whats the 3 main functions brake pistons fulfil ?

Answer 51

Apply brake force Compensate for wear of brake Adjust brake clearance

Question 52

What provides the supply of hydraulic pressure to apply the bakes I large aircraft that do not have a master cylinder ?

Answer 52

Power brake control valve ( meters hydraulic fluid to the corresponding brake assembly matching the pressure applied to the pedal )

Question 53

What provides the supply of hydraulic fluid to apply the brakes on a light aircraft ?

Answer 53

Master cylinder ( when pedal is depressed, master cylinder forces hydraulic fluid through a line to the pistons in the brake assembly )

Question 54

Why would a brake debooster be installed ?

Answer 54

If you don’t need all hydraulic pressure to use the brakes

Question 55

How does a parking brake work ?

Answer 55

Brake pressure is remained in brake system due to a shutoff valve in the return line. ( done by hydraulic accumulator pressurised by nitrogen )

Question 56

Whats emergency backup options for brake systems ?

Answer 56

Separate hydraulic power source Brake accumulator.

Question 57

Where are brake temps and overheat warnings displayed ?

Answer 57

ECAM - airbus EICAS - Boeing

Question 58

What does the anti-skid system do ?

Answer 58

If it detects that the wheel speed and aircraft speed is different, brake pressure is not directed to piston and instead is directed to the return

Question 59

What does touchdown protection prevent ?

Answer 59

A tyre blow out upon landing by not allowing brakes to be applied until aircraft’s wheels have touched down onto the runway. ( anti-skid valve connects system to return until there is weight on wheels so that the brakes cannot be operated )

Question 60

When does the auto-brake system begin to work ?

Answer 60

When there is weight on wheels and thrust reversers are deployed

Question 61

What’s the bead function on a tyre ?

Answer 61

Strengthen the carcass and mount tyre to wheel

Question 62

Whats the carcass ply’s function on a tyre ?

Answer 62

Give tyre strength and is layered

Question 63

Continue tyre properties

Question 64

What does a shimmy damper do ?

Answer 64

Dampens oscillations and found on upper torque link on nose gear

Question 65

What does having main landing gear steering reduce ?

Answer 65

Tyre scrub `

Question 66

Why is there a pin inserted in to the nose wheel ?

Answer 66

Isolates nose wheel from cockpit controls which doesn’t allow pilots to move the wheel. ( steering commands doesn’t reach actuators )

Question 67

Where is the air/ground sensor installed on an aircraft ?

Answer 67

On the upper Torino link and sometimes on the collar

Question 68

Explain a load sensor to determine weather the airplane is in the air or on the ground ?

Answer 68

Senses the landing gear beams bending when the weight of the aircraft is on the gear