Brakes

Question 1

Brake fade

Answer 1

Result of brakes overheating

The brakes will not be able to absorb any further energy

Will fail with pressure still applied to the break pedal

Overheated brakes may judder

Question 2

Brake drag

Answer 2

Brake is coming on but not coming off correctly

Wrongly adjusted or faulty brake adjuster - may contribute to brake fade

Question 3

Multi plate brake operation

Answer 3

Consists of interleaved stators and rotors

Brake application compresses the stator disks together and brings them into contact with the rotors

Question 4

Multi plate brake components and their functions

Answer 4

Rotors - tongues that look onto the wheel
Torque plate - pistons operated by hydraulics, push the sandwich together
Adjuster - makes sure there is enough clearance

Question 5

Plates are made of

Answer 5

Heavy steel with a special case hardened surface carbon

Question 6

Why are brake plates case hardened

Answer 6

To prevent thermal shock

Question 7

In the event of wheel or brake fire - what to use

Answer 7

Dry powder

Liquid may cause the pads to explode

Question 8

How to judge brake wear

Answer 8

By checking how much the retraction pin protrudes from the brake housing - with the brakes on or applied

Question 9

Advantages of carbon brakes

Answer 9

Lighter
Absorbs twice as much heat as steel
Less prone to brake fade - can still happen tho
Last longer but more expensive to fit initially

Question 10

Anti skid systems

Answer 10

Monitors individual wheels - reduces pressure to a specific wheel then re applies pressure - process happens very rapidly

Monitors wheel rotation

Question 11

Intelligent braking/ bias modulation

Answer 11

Every time the brake applies pressure - will reduce the pressure by a small amount each time

Question 12

Advantages of an electrical anti skid

Answer 12

Music quicker response rates than mechanical and modulation is matched closer to actual r/y conditions

Easier to adapt the system to different a/c and can be tested prior to use

Question 13

3 main components of electrical anti skid

Answer 13

Wheel speed/signal gen

Control box to compute wheel sped information

Servo valve to modulate brake pressure

Question 14

Electronic anti skid operation

Answer 14

Uses a small gen driven by the wheel assembly

Anti skid controller cross references signals from all the wheels - estimates a/c speed based on wheel speed - predicts the slip ratio - at a set value - reduces pressure to that wheel - allows it to spin back up - pressure is re applied at a lower pressure to find the max braking force

Question 15

Anti skid unit functions

Answer 15

Skid prevention - heart of the system

Locked wheel protection - monitors individual wheels for locking rather than skidding

Touch down protection - stops you l/d with foot on the brakes - applies auto brakes under certain criteria

Hydroplane protection - looking at all the wheels on the set to be locked

Question 16

Anti skid is deactivated at

Answer 16

20 mph

Either manually or automatically

Question 17

Touch down bounce protection

Answer 17

If the a/c bounces after the initial touchdown - the system releases any brake pressure allowing the wheel to spin up again before the second touchdown

Question 18

Locked wheel protection

Answer 18

If the wheel locks because of wet patch or ice - controller will release the pressure to that wheel completely - then re apply

Question 19

If both the normal and alternate hydraulic system fails - brakes

Answer 19

An accumulator is automatically selected

Question 20

Torque limiting - brakes

Answer 20

Sensor is provide on each wheel - brake bar - senses torque during braking - prevents you putting too much strain on the l/d gear - pressure will be released - more of a problem with carbon brakes

Question 21

Auto-brakes will not work when

Answer 21

A fault occurs - automatically disconnect

Auto brakes are not available when using the alternate braking system or s/by

Question 22

Auto brakes in the armed posn takes indications from

Answer 22

Weight on wheels

Bogie orientation

A signal from 2 separate wheels

Question 23

RTO mode

Answer 23

Rejected t/o mode

Max brake pressure will be applied when all thrust levers are closed at ground speeds above 85kts - on all the wheels

Pre flight check - select RTO

Question 24

When will the autobrake move to the disarm posn

Answer 24

If a fault occurs

Operation of foot brakes

Advancing of any foot brakes

Moving the speed brake lever down after speed brakes have been deployed on the ground

Normally disarm by a non handling pilot/ ground engineer as the a/c slows to 20kts

Question 25

Slip ratio

Answer 25

Main wheels spinning faster than the nose wheel - if this occurs - put brake on