Landing Gear and Brakes

Question 1

Which hydraulic system(s) operates the landing gear?

Answer 1

Normally system A

System B, if
-Airborne,
-#1 engine N2 < 50%, and
-Landing gear selected UP and gear not up

Question 2

Which hydraulic system(s) can pressure the parking brake?

Answer 2

Hydraulic system A or B, normally

Brake accumulator for up to 8 hours

Question 3

If the #1 engine fails how is hydraulic system A affected? How is the gear raised?

Answer 3

Hydraulic system A operates at reduced output (electric hyd pump is smaller than the now inoperative engine pump)

Landing Gear Transfer Unit
-Allows hydraulic system B to raise landing gear if
-Airborne,
-#1 engine N2 < 50%, and
-Landing gear selected UP and gear not up

Question 4

How can the landing gear be lowered without hydraulic pressure? Can it be raised?

Answer 4

Manual gear extension handles

Gear cannot be raised w/o hydraulic pressure
-System A (or B if Landing gear transfer valve criteria met)

Question 5

When is the landing gear lever locked? Can it be overridden?

Answer 5

Lever locked on the ground (prevent inadvertent retraction)

Landing gear lever lock may be overridden in certain conditions (see QRH)

Question 6

When must RTO be selected? When is RTO braking available?

Answer 6

RTO must be selected on the ground
-Also prior to 60 knots and thrust levers idle

RTO braking available when wheel speed > 90 knots

Question 7

What could cause the ANTISKID INOP (amber) light to illuminate?

Answer 7

Fault in anti-skid system, or

Fault in parking brake system

Question 8

What do the red/green gear position lights indicate?

Answer 8

Green – gear down and locked

Red
-Gear is not down and locked (thrust lever IDLE and < 800’RA)
-Gear in disagreement w/ lever position (in-transit or unsafe)

Question 9

What is the purpose of the aft overhead panel landing gear indicator lights?

Answer 9

Backup gear indicators using dedicated proximity switches

One GREEN gear light for each gear – Gear is down and locked
*can be from either panel

Question 10

Is the alternate brake system capable of applying auto brakes?

Answer 10

No, auto brakes require:
-Normal brake system,
-Anti-skid, and
-Hydraulic system B pressure

Question 11

What protects the aircraft from loose tread or FOD in the main wheel well during gear retraction?

Answer 11

Frangible fitting

When impacted, relieves hydraulic pressure from respective retraction line

Affected gear cannot be retracted until fitting is replaced

Question 12

How is nose wheel steering powered?

Answer 12

Hydraulic system A normally

Hydraulic system B if
-NOSE WHEEL STEERING switch to ALT,
-Aircraft on the ground, and
-Hydraulic B quantity > 21%

Uses landing gear transfer valve

Question 13

If normal and alternate brake pressure is lost, how is braking accomplished? Any limitations?

Answer 13

Brake accumulator (anti-skid still available)

6 brake applications OR parking brake for 8 hours

Question 14

How are the tires protected from explosion due to thermal expansion from hot brakes?

Answer 14

4 thermal fuse plugs in each main wheel melt to release tire pressure

All 6 tires also have an over-pressure relief valve to release tire pressure

Question 15

What does a Parking Brake Warning (red) light indicate?

Answer 15

Parking brake shutoff valve is not full open
-Hot battery bus power

Parking brake lever latches when parking brake set with adequate hydraulic pressure

Question 16

What braking systems have anti-skid? What does anti-skid provide?

Answer 16

All braking systems have anti-skid
-Individual wheel antiskid for Normal AND accumulator brakes
-Wheel pair antiskid for Alternate brakes

Anti-skid provides
-Skid protection
-Locked wheel protection
-Touchdown protection
-Hydroplane protection