Unit 2-5

Question 1

What is the main purpose/function of landing gear?

Answer 1

Supports the aircraft during ground operations
Dampens vibrations when taxiing
Cushions landing impact

Question 2

What are the three configurations of landing gear?*

Answer 2

Tricycle landing gear - nose wheel
Conventional landing gear - tail dragger
Bicycle landing gear

Question 3

What are the two main categories of landing gear?

Answer 3

Fixed
Retractable

Question 4

What is fixed category landing gear?

Retractable category landing gear?

Answer 4

Gear always extended
Found on less complex aircraft

Gear extended for landing and take off
Gear retracted for flight

Question 5

List advantages and disadvantages of retractable category landing gear

Answer 5

Advantages:
More aerodynamic
Saves fuel

Disadvantages:
More complex
More expensive

Question 6

What does the trunnion attach together?

What does it do?

Answer 6

Attaches landing gear assembly to airframe

Pivots during extension and retraction

Question 7

What is the shock strut?

What does it do?

Answer 7

A self-contained hydraulic unit

Supports the weight of an aircraft while the aircraft is on the ground
Protects the aircraft structure by absorbing and displacing shock loads during landing

Question 8

What does the truck do?

Answer 8

Used when wheels are in tandem, multi-wheel aircraft
Tilts fore and aft with the attitude of the aircraft

Question 9

What do the torque arms (scissors) connect?

What does it do?

What part should be inspected on pre-flight?

Answer 9

Connects shock strut to truck

Restrict the extension of the shock strut during gear retraction
Holds wheel and axle in alignment with the shock strut

Bolt holding wheel to strut
Wheel will fall off without it tight

Question 10

What does the drag brace do?

Answer 10

Stabilize the landing gear assembly longitudinally and laterally
Replace torque arms on larger aircraft

Question 11

How do air-oleo struts work?

Answer 11

Fluid passing through orifice acts to absorb shock of compression
The fluid is not-compressible so it slows the strut collapse as the fluid passes through the orifice

Metering pin gets larger as you go down
As more hydraulic passes through the orifice and the landing gear is compressed, the metering pin allows less and less fluid to pass through
Slows down compression

Question 12

How do energy returning struts work?

Answer 12

Spring steel landing gear absorbs the shock of landing
Like a spring - returns the energy back to the aircraft

Question 13

Describe an aircraft wheel

Answer 13

Wheel is split in to 2 halves held together with “through bolts” or “tie bolts”
Magnesium or aluminum alloy construction (very light)

Question 14

What are the two types of wheels?

Answer 14

Tube
Tubeless

Question 15

What gas is used to fill aircraft tires?

Why?

Answer 15

Nitrogen or argon

Expanding and contracting air can produce heat and moisture
Nitrogen is a more dry gas
Condensation can cause corrosion

Question 16

Describe tube type wheels

Answer 16

Inner tube seals the air inside
Gets put on a wheel then a tire over it

Question 17

Describe tubeless type wheels

Answer 17

“O” ring between the two halves of the wheel to keep the air in the tire
Air is kept between the tire and the wheel itself

Question 18

What is the purpose of wheel fuse plugs?

Answer 18

Allow the plug to blow out and release the tire pressure before the wheel blows up
Plug is angled so it bounces off of the side of wheel to reduce its velocity to that of less than a bullet, but they can still seriously hurt and injure you

Question 19

How does the wheel mount to the axle of the aircraft?

What happens when it is over/under tightened?

Answer 19

A single axle nut in the center of the wheel
A cotter pin retains the axle nut on the axle

Over tighten the axle nut wedges the bearings tightly towards each other and cause the bearing to overheat and fail

Not tightening the nut enough and bearings can fail as the wheel shifts back and forth on the axle

Question 20

What data is presented on wheel data plates?

Answer 20

TSO number tells that this is an approved aircraft part
Part number of the wheel
Who manufactured the wheel
The torque value for the tie bolts
Size tire the wheel will accept