Unit 2-6

Question 1

What is the purpose of brake systems?

Answer 1

Stop the aircraft
Hold wheels locked for parking

Question 2

How do independent brake systems work?

Answer 2

Brake pedals activate pushrod to move the individual master cylinder and push fluid from a reservoir into the hydraulic lines to brake

Question 3

How do integral power brake systems work?

Answer 3

Use main system hydraulic pressure for braking
Reservoir, gear pump, pressure relief valve, check valve, selector valve, actuator, back to reservoir
Must have a backup system (accumulator)

Question 4

What is the difference between and independent brake system and an integral power system?

Answer 4

Independent system has one master cylinder per brake, its own hydraulic system
Integral system uses the aircraft hydraulic system and uses it for braking

Question 5

How do drum brakes work?

What are the components?

Answer 5

Drum rotates, shoes stationary
Hydraulic pressure presses the brake shoe against the drum

Two piston actuating cylinder
Shoe returning spring
Brake shoes
Pivot pins

Question 6

How do disc brakes work?

What are the components?

Answer 6

Piston is hydraulically moved which then moves the linings against the brake disc

Disc
Linings (brake pads)
Hydraulic system
Calipers

Question 7

What are the two types of disc brakes?

What is the difference between them?

Answer 7

Floating
Fixed

Floating has a piston on one side
Fixed has pistons on both sides

Question 8

How is the disc brake better than the drum brake?

Answer 8

Better at dissipating heat

Question 9

How are multiple disk brakes better?

Answer 9

More surface area - better friction – better braking

Question 10

How do multiple disk brakes work?

Answer 10

Multiple pistons push simultaneously with hydraulic pressure
Instead of a lining with a pad, there are stator carbon disks between the rotor carbon disks
Pistons push the stack of disks together
Pistons need to apply constant pressure

Question 11

Is hydraulic fluid in the brake lines compressible? Why or why not?

What happens when there is air in the brake lines?

Answer 11

Hydraulic fluid in the brake lines is not compressible so it can instantly transmit force from a brake pedal (master cylinder) to the brake cylinder on the wheel

The air compresses and the energy input at the pedal does not get transmitted to the wheels
When brake pressure is applied, the air bubble just compresses (doesn’t move through the system)
It must be removed from the system in order for the brakes to operate correctly (drain the line)