Landing Gear, Brakes, and Nosewheel Steering

Question 1

What holds the MLG in the extended position?

Answer 1

Mechanical over centering with down locks.

Question 2

What holds the nose gear in the retracted position?

Answer 2

A spring loaded, over-center type locking mechanism.

Question 3

What holds the main gear in the retracted position?

Answer 3

Mechanical uplocks and hydraulic system 3 pressure.

Question 4

What controls the landing gear?

Answer 4

The Proximity Sensing Electronic Unit (PSEU).

Question 5

After the nose gear is extended, do the gear doors close?

Answer 5

No, any time the nose gear is down the doors are open.

Question 6

What ensures the nose wheel is centered prior to retraction into the well?

Answer 6

The ECU sends a signal to center after takeoff, and then a centering cam keeps it centered when hydraulic pressure is removed.

Question 7

What complications can be expected if both hydraulic systems 2 and 3 fail?

Answer 7

The nose wheel will not extend for landing.

Question 8

Which hydraulic system is used to raise and lower the gear?

Answer 8

Hydraulic system 3.

Question 9

When will the “TOO LOW GEAR” aural warning sound?

Answer 9

With a radar altitude below 500 feet at a speed of less than 190 KIAS.

Question 10

What is the maximum steering angle for the nose tiller and rudder, respectively?

Answer 10

80º, and 8º.

Question 11

Why is it important not to move the tiller in flight with the gear extended?

Answer 11

The steering will be inoperative as annunciated by a STEER INOP message on the EICAS upon landing; however, you will have no warning in flight.

Question 12

What is locked wheel protection?

Answer 12

The Antiskid Control Unit (ASCU) monitors each wheel to ensure even rotation. If one wheel enters a skid and is at least 30% slower than the others, the ASCU will release brake pressure to that wheel to balance the rotation speeds.

Question 13

What is touchdown protection?

Answer 13

This guards from inadvertant landing with the brakes applied if the pilot is pressing the brake pedals. Braking will not be applied until a wheel spin up of 35 knots is acheieved, or weight on wheels plus 5 seconds.

Question 14

What colors does the Brake Temperature Monitoring System display brake heat in?

Answer 14

• Green - Normal range between 0 and 6.
• White - Caution range between 7 and 14.
• Red - Overheat range between 15 and 20.

Question 15

How can an actual temperature be calculated based on the BTMS readings?

Answer 15

Take the readout value and multiply by 35 to detirmine actual brake temp.

Question 16

After a landing or rejected takeoff, what is the minimum turn around time?

Answer 16

15 minutes to insure max brake temperature is reached.

Question 17

Where is the brake energy chart found?

Answer 17

QRH volume 1.

Question 18

Can braking be accomplished through the use of accumulator pressure?

Answer 18

Yes.

Question 19

How many brake applications are available from an accumulator charge?

Answer 19

Up to six.

Question 20

What are the brake accumulators charged to?

Answer 20

750 psi.

Question 21

How are the tires thermally protected from blowout?

Answer 21

Through the use of four thermal fuse plugs in each wheel?

Question 22

Can the brake wear indicators be checked without brakes applied?

Answer 22

No, both hydraulic systems 2 and 3 must be activated and the brakes applied.

Question 23

How does the parking brake work?

Answer 23

The parking brake shutoff valve is used to lock the brakes on by trapping hydraulic system 3 pressure. When the hydraulic systems are shutdown system 3 accumulator pressure should keep the brake applied for an extended period of time.