Landing Gear

Question 1

How many weight on wheels switches are there and where are they?

Answer 1

5 total
2 each main gear
1 on nose wheel.

Question 2

How many WOW signals does it take to release the air ground signal output?

Answer 2

3 signals

Question 3

If one WOW signal is invalid how many have to agree before the air ground output will be released?

Answer 3

2

Question 4

If 2 WOW signals are invalid how many will be processed?

Answer 4

2

Question 5

How many proximity switches are there? And where are they located?

Answer 5

19 total
5 WOW - 2 each main 1 nose
12 up and down - 2 per wheel
1 steering - 7 degree limit 
1 nose gear doors

Question 6

Which hydraulic system operates the gear?

Answer 6

1

Question 7

How are the main gear doors opened and closed?

Answer 7

By a mechanical linkage connected to the main gear.

Question 8

How are the nose gear doors opened and closed?

Answer 8

Hydraulically at 3000psi.

Question 9

How is the gear held up?

Answer 9

Mechanical uplock hooks

Question 10

How many main gear actuators are there and what do they do?

Answer 10

2 one to retract the gear. One to release the over center down lock.

Question 11

What are the 3 ways to extend the gear?

Answer 11

Landing gear lever
Electric override
Free-fall lever

Question 12

How is the gear held down?

Answer 12

Through an over center locking mechanism.

Question 13

What protects the gear from being retracted on the ground?

Answer 13

A lock on the landing gear lever

Question 14

What are the 3 positions of the override switch and their use?

Answer 14

Normal
Doors - opens nose gear doors
Gear doors - extends gear

Question 15

How does the free fall lever lower the gear?

Answer 15

A mechanical linkage pulls the up locks open.

Question 16

How does the override switch extend the gear?

Answer 16

By bypassing the LGEU and sending the the signal directly to the landing gear electro valve.

Question 17

When does the landing gear warning go off?

Answer 17

Below 1200’ 1 thrust lever below 59 and the other below 45, any flaps setting

1. Flaps 0-9 can be cancelled
2. Flaps 22-45 can not be cancelled
3. Flaps 45

Question 18

When does the EGPWS give a “too low gear” alert?

Answer 18

Below 500’

Less than 190kts

Question 19

How is the main landing gear mounted?

Answer 19

A trailing link