Landing Gear & Brakes

Question 1

Which hydraulic system power the landing gear?

Answer 1

Center system

Question 2

Is the system still pressurized with the gear retracted?

Answer 2

No

Question 3

Can the gear be retracted after an alternate extension?

Answer 3

Yes, provided the center hydraulic system is functional.

Question 4

What is the greatest angle the rudder pedals & tiller will turn the nose gear?

Answer 4

Rudder - 8 degrees

Tiller - 70 degrees

Question 5

Which system powers the brakes? Is there a backup?

Answer 5

Brakes powered electrically by 28Vdc system. Backup is battery power.

Question 6

How does alternate landing gear extension work?

Answer 6

Dedicated DC hydraulic pump releases uplocks using center system fluid. Landing gear free-falls in to down and locked position.
Gear lever position has no effect on alternate extension.
All hydraulically powered gear doors will remain open after extension.

Question 7

With RTO selected, when would the brakes be applied?

Answer 7

• Airplane is on the ground
• Groundspeed above 85kts
• Both thrust levers retarded to idle

Question 8

What will disarm the brakes after landing?

Answer 8

• Pedal braking applied
• Either thrust lever advanced
• Speedbrake lever moved down after speedbrakes have deployed
• DISARM or OFF selected on the autobrake selector
• Autobrake fault
• Normal antiskid system fault
• Loss of inertial data from the IRU’s

Question 9

Where are the brake temperatures displayed?

Answer 9

Synoptic GEAR page

Question 10

How can the parking brake be confirmed as set?

Answer 10

By observing the EICAS memo message “PARKING BRAKE SET”

Question 11

What is the “park and adjust” feature?

Answer 11

A feature which monitors the condition of the brakes after application and adjusts the clamping force as needed during brake cooling.

Question 12

Is there an active force on the EBA’s when the parking brake is set?

Answer 12

No, brakes are clamped on and no force required.

Question 13

When does the autobrake application start on landing?

Answer 13

• Both thrust levers retarded to idle

- Wheels have spun up

Question 14

Is there any limitation on the MAX AUTO brake selection?

Answer 14

Deceleration is limited to 4 until pitch angle is less than 1 degree

Question 15

Above what value will the BRAKE TEMP indication change to amber and show the associated EICAS?
When does it change back to white?

Answer 15

5.0 or above

Changes back when all brakes are below 3.0

Question 16

When is taxi brake release active?

Answer 16

787-8 - Below 70kts

787-9 - Below 30kts

Question 17

When is the EICAS “TIRE PRESS” displayed?

Answer 17

• When any tire pressure is above or below the normal range.
• When there is excessive diff between two tires on the same axle.

Question 18

How many Electric Brake Actuators are there per main wheel brake?

Answer 18

4 EBA’s per wheel brake, 32 in total.

Question 19

How many EBAC’s are there?

Answer 19

4 Electric Brake Actuator Controllers. Each control a fore-aft wheel pair.

Question 20

What happens when a wheel speed sensor senses a skid?

Answer 20

Brake pressure is reduced until skidding stops

Question 21

Is antiskid provided for each individual wheel?

Answer 21

Yes

Question 22

What data is used for touchdown and hydroplaning protection in the antiskid system?

Answer 22

Airplane inertial data

Question 23

What data is used for locked wheel protection?

Answer 23

Comparison with other wheel speeds.

Question 24

How long after the EICAS indication changes from UP to blank after retraction?

Answer 24

10 seconds

Question 25

How can the isolation valves be controlled by the crew?

Answer 25

They can not

Question 26

What is the purpose of the NGIV, RSIV and the AEIV?

Answer 26

Together with a reservoir standpipe in the center hydraulic system, the isolation valves will provide isolation functionality in the event of a leak. Flight crew will be able to extend the landing gear and have operational nose wheel steering on landing.

Question 27

After retraction, how is the gear held up?

Answer 27

Gear is held up by mechanical uplocks. Up lock hook in over center position by springs, holding the gear even with hydraulic pressure off.