Landing Gear and Brakes

Question 0

How many weight-on-wheels proximity sensors are there

Answer 0

6

Question 1

How many proximity sensor electronic modules (PSEM) are there

Answer 1

2

Question 2

How any WOWs on each gear

Answer 2

2

Question 3

What happens if 2 WOW sensors k. The same wheel are failed

Answer 3

PSEMs prohibit gear from being raised

Question 4

When up, what holds the landing gear in place

Answer 4

Uplocks

Question 5

How are the landing gear doors operated

Answer 5

Mechanically

Question 6

How is the landing gear held in the down position

Answer 6

Downlock springs

Question 7

What is the electrical override system

Answer 7

When the landing gear lever control box fails, the electrical override system bypasses the PSEM and commands the gear down normally

Question 8

When do you use the alternate gear extension

Answer 8

When the hydraulic pressure is lost or electrical system fails

Question 9

How does the alternate gear extension system work

Answer 9

Hyd pressure is released from all uplocks and the gear free falls into position

Question 10

Which brake does hyd 1 control

Answer 10

Outboard

Question 11

Which brake does hyd 2 control

Answer 11

Inboard

Question 12

What are the main functions of Brake Control Modules

Answer 12

• Locked wheel protection
• antiskid protection
• Automatic wheel braking
• touchdown protection

Question 13

What is locked wheel protection

Answer 13

The BCM compaira wheel speeds and releases brake pressure on the slower wheel if it is 33% slower to match speeds

Question 14

Why the threshold for wheel lock protection

Answer 14

To allow for differential braking

Question 15

Under what speed is antiskid protection not available

Answer 15

10kts

Question 16

What is automatic wheel braking

Answer 16

Automatically stops the wheels from spinning while being retracted

Question 17

What is touchdown protection and when is it deactivated

Answer 17

Prevents landing with main wheel brakes on.

Deactivated 3 secs after WOW has sensed landing or when wheel speed is above 50 kts

Question 18

What powers the emergency/parking brake

Answer 18

Hyd 1 and 2

Question 19

What happens to the emergency/parking brake if you lose hyd 1 and 2

Answer 19

Can still apply emergency brake 6 times because of the emergency brake accumulators

Question 20

Are antiskid, touchdown, and locked wheel protection provided while auto braking

Answer 20

Yes

Question 21

When will landing and RTO auto braking be disarmed

Answer 21

• selector switch is set to the OFF position
• pedal braking is applied if speed is above 60 kts and RTO is selected
• brake control system failure is detected (while speed below 60 and RTO selected)
• either thrust lever is advanced above idle during autobrake application.

Question 22

Will autobrake discontinue on landing if manual brakes are applied

Answer 22

Yes, if pressed more than 20%

Question 23

Which hyd system powers the nose wheel steering

Answer 23

2

Question 24

What are the 3 nose wheel steering modes

Answer 24

Hand wheel
Rudder
Free wheel

Question 25

What is needed to engage the nose wheel steering

Answer 25

• hyd 2 pressure
• the external steering disengage switch must be in the engaged position
• the hand wheel steering must be pressed and released for rudder steering or pressed and held for hand wheel steering

Question 26

What are the different maximum steering angles for handwheel steering

Answer 26

Below 10 kts : +/- 76 deg
Around 26 kts : max is 20 deg
Over 100 kts : max is 7 deg

Question 27

What is max steering angle of rudder pedals

Answer 27

7 deg