Landing Gear and Brakes

Question 1

How is the landing gear extended and retracted?

Answer 1

Electronically commanded and hydraulically actuated

Question 2

When will the aural warning for the landing gear sound?

Answer 2

• If the gear is not down and locked, and

- 5

Question 3

Can the landing gear aural warning be silenced by pushing the ‘LG WRN INHIBIT’ button?

Answer 3

Only is both Radio Altimeters have failed

Question 4

What are the 3 Landing Gear extension modes?

Answer 4

• Normal - LG lever Down
• Electric Override - Bypasses PSEM to directly command selector valve
• Alternate Gear Extension - Manual uplock release opens free-fall sequencing valve

Question 5

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

Answer 5

• Mechanically releases the landing gear lever lock

- Lock protects against inadvertent landing gear retraction when WOW

Question 6

What keeps the gear in the locked position?

Answer 6

• Extended - Down lock springs

- Retracted - Uplock hooks

Question 7

Describe the Landing gear indications

Answer 7

-Green - Down and Locked
-White - Up and locked
-Amber - In transit
Red - Gear position and lever disagreement (20sec grace period)

Question 8

How do the landing gear doors actuate?

Answer 8

Mechanically, during landing gear extension or retraction

Question 9

How are the brakes commanded?

Answer 9

• Brake by Wire
• Electrically commanded and hydraulically actuated
• Pedal position transducers send brake requests to the BCM (Brake Control Module)

Question 10

What Hydraulic system(s) provide brake pressure?

Answer 10

• HYD 1 - Outboard brakes
• HYD 2 - Inboard brakes
• HYD 3 - Parking/Emergency Brake

Question 11

What protections are provided for braking?

Answer 11

• Touchdown - No braking until 3 seconds or >50kts wheel speed after touchdown
• Anti-skid - Compares wheel speeds and releases pressure (inop

Question 12

How many applications will the parking/emergency brake provide?

Answer 12

6 applications

Question 13

What stops the wheels from spinning during retraction?

Answer 13

• Main - BCM applies brakes after Weight off Wheels

- Nose - Snubbers in the nose bay stop the wheels

Question 14

Which HYD System controls the nosewheel steering

Answer 14

HYD 2

Question 15

What are the limits for the nosewheel steering?

Answer 15

• Angle varies with ground speed
• Up to 40kts +76°
• 41 to 100kts Decreases linearly from 76° to 7°