Landing Gear and Brakes - Question Bank

Question 1

Describe the OFF position of the landing gear.

Answer 1

Landing gear hydraulic system is depressurized.

Question 2

How many degrees can the nose-wheel steering system turn the nose gear with the tiller, and how many degrees with the rudder pedals?

Answer 2

• 70 degrees in either direction with the tiller

* 7 degrees with the rudder pedals

Question 3

When does RTO apply maximum brake pressure?

Answer 3

• Airplane on the ground
• All 4 thrust levers are closed, and
• Above 85 knots.

Question 4

What does the BRAKE SOURCE amber light indicate when illuminated?

Answer 4

Active brake hydraulic sources (hydraulic systems 4, 1, and 2) have low pressure

Question 5

What does a white, crosshatched, expanded gear position indication mean?

Answer 5

Respective landing gear in transit

Question 6

What does an amber X display on an expanded gear position mean?

Answer 6

Landing gear position indicator inoperative

Question 7

What does a white empty box on the Gear synoptic display indicate?

Answer 7

Respective landing gear door position indicators inoperative

Question 8

What sensing systems control in flight and ground operation of various airplane systems?

Answer 8

• Air/ground sensing system

* Nose gear extension sensing system

Question 9

How does the airplane distinguish between air mode and ground mode?

Answer 9

A combination of main gear tilt sensors

Question 10

Nose gear extension sensing provides a signal to relays controlling functions in which systems?

Answer 10

• Stall warning

* Nose gear steering

Question 11

What conditions must be satisfied in order for the landing gear lever lock to release? (From down–> up position)

Answer 11

• Main gear are tilted

* Body gear centered

Question 12

Describe the sequence of events when the landing gear lever is moved UP.

Answer 12

• The landing gear doors open
• Automatic braking occurs
• Landing gear begin to retract.
• EICAS gives related indications

Question 13

How are the landing gear held in position after retraction?

Answer 13

• Main gear are held in the up position by uplocks

* The nose gear is mechanically locked in the up position.

Question 14

During landing gear extension, state what happens if any gear position disagrees with lever position after normal transit time.

Answer 14

• The EICAS changes to the expanded non-normal format

* Affected gear displayed as in transit, or UP if the gear never unlocked from the up position.

Question 15

How does the gear extend through the alternate gear extension system?

Answer 15

• By pushing the Alternate Gear Extend switches
• The gear uplocks and gear door latches are electrically released.
• The gear free-falls
• Gravity and air loads extend the gear
• Springs pull the downlocks into the locked position

Question 16

When does body gear steering operate?

Answer 16

When the nose wheel steering angle exceeds 20 degrees

Question 17

When is body gear steering activated and when is it deactivated?

Answer 17

• Ground speed decreasing through 15 knots

* Ground speed increasing through 20 knots

Question 18

What is the purpose of the brake accumulator?

Answer 18

Provides parking brake application

Question 19

Describe the difference between normal and alternate anti-skid braking systems.

Answer 19

• Normal brake antiskid provides each main gear wheel with individual
antiskid protection.
• Alternate brake antiskid provides antiskid protection to lateral wheel pairs
(forward and/or aft pair on each truck), rather than to individual wheels

Question 20

How does the brake torque limiter function in the Alternate brake system?

Answer 20

• Brake torque is sensed on an individual wheel basis.
• Signal sent to alternate anti-skid valve.
• Brake pressure is released on a laterally paired wheel basis.

Question 21

When do the auto brakes apply after landing?

Answer 21

• All thrust levers are closed
• Ground mode sensed
• The wheels have spun up

Question 22

Which systems contribute to total airplane deceleration on landing and reduces autobrake pressure?

Answer 22

• Thrust reverse

* Spoilers

Question 23

Give examples of what would disarm the autobrakes after landing.

Answer 23

• Pedal braking applied
• Any Thrust lever advanced after landing
• Speedbrake lever moved to DOWN detent after speedbrakes have been
deployed on the ground
• DISARM or OFF position selected on the Autobrakes selector
• Autobrake fault
• Normal antiskid system fault
• Loss of normal hydraulic pressure

Question 24

What hydraulic system pressurizes the brake accumulator?

Answer 24

System 4

Question 25

Can the airplane be stopped with normal accumulator pressure?

Answer 25

No, the accumulator is not designed to stop the aircraft.

Question 26

Why is it necessary to pressurize hydraulic system 4 before pressurizing the other systems?

Answer 26

Precludes the transfer of hydraulic fluid from system 1 or 2 into system
4, when the parking brake is set, and then released.

Question 27

What provides automatic brake source selection?

Answer 27

Pressure-operated selector valves

Question 28

What value on the brake temperature monitoring system causes the BRAKE TEMP Advisory EICAS message to appear?

Answer 28

5