Landing Gear

Question 1

When will the aural warning for the landing gear sound?

Answer 1

If the gear is not down and locked, and
Less than 700’ RA and low TLA, or
Any altitude with flaps set greater than 5

Question 2

Can the landing gear aural warning be silenced by pushing the LG WRN INHIB button?

Answer 2

Only if both radio altimeters have failed

Question 3

What are three landing gear extension modes?

Answer 3

Normal…… LG lever DOWN
Electric override…. Bypasses PSEM to directly command selector valve
Alternate gear extension……Manual release opens free-fall sequencing valve

Question 4

What is the purpose of the DN LOCK RLS button on the landing gear lever?

Answer 4

Mechanically releases the landing gear lever lock

Lock protects against inadvertent landing gear retraction when weight-on-wheels.

Question 5

What keeps the gear locked in position?

Answer 5

Extended…..downlock springs

Retracted…..uplock hooks

Question 6

Describe the landing gear indications

Answer 6

Green…..down and locked
White……up and locked
Amber……..in transit
Red……..gear position and lever disagreement (20 sec grace period)

Question 7

How do the landing gear doors actuate?

Answer 7

Mechanically, during landing gear extension or retraction

Question 8

How are the brakes commanded?

Answer 8

Brake by wire
Electrically commanded and hydraulically actuated
Pedal position transducers send brake requests to the BCM (brake control module)

Question 9

What hydraulic system(s) provide brake pressure?

Answer 9

HYD 1…..outboard brakes
HYD 2……inboard brakes
HYD 1 and 2…..parking/emergency brake

Question 10

What protections are provided for braking?

Answer 10

Touchdown….no braking until 3 seconds or wheel speed more than 50 kts after touchdown.

Ant-skid…. Compares wheel speeds and releases pressure ( inop less than 10 kts)

Locked-wheel… Allows up to 33% differential braking for steering prurposes (inop less than 30 kts)

Question 11

How many applications will the parking/emergency brake provide?

Answer 11

6 applications

Question 12

What stops the wheels from spinning during retraction?

Answer 12

Main gear…BCM applies brakes after weight-off-wheels

Nose gear…. Snubbers in the nose bay stop the wheels

Question 13

Which hydraulic system controls the nosewheel steering?

Answer 13

HYD 2

Question 14

What are the limits for the nosewheel steering?

Answer 14

Angle varies with ground speed:

Up to 40 kts….76°
41 to 100 kts…. Decreases linearly from 76° to 7°

Question 15

How is the landing gear extended and retracted?

Answer 15

Electrically commanded and hydraulically actuated

Question 16

Describe the towing lights?

Answer 16

GREEN:
Steering disengaged through the external steering disengage switch and
Parking brakes not applied and
Main brakes not applied.

RED:
External steering disengage switch in the engaged position or Parking brakes applied or
Main brakes applied.

Question 17

How many uplocks and downlock are on the airplane?

Answer 17

12 total

2 uplocks and 2 downlocks on each landing gear

Question 18

How many weight on wheel sensors are on the airplane?

Answer 18

6 total

Two on each wheel

Question 19

Do all weight on wheel sensors have to agree to get a good indication?

Answer 19

No, one sensor that is in agreement with the handle position will provide a positive indication.