14 Landing Gear Flashcards
What inputs does air/ground sensing system use to configure the airplane systems to the appropriate air or ground status?
Air/ground logic signals from sensors located on each main landing gear beam.
a. What does the landing gear consist of? b. Which elements are steerable?
c. How many wheels are there on each main truck?
a. Two main landing gear and a single nose gear b. Nose gear
c. Four
Which hydraulic system powers the landing gear?
The Centre system
a. What condition removes the lever lock?
b. What action is required to raise the gear if the lever is locked?
a. Air/ground sensing
b. Pushing and holding the landing gear lever LOCK OVERRIDE switch
a. After retraction, how is the gear held up? b. Is the system still pressurised?
a. By uplocks
b. No, the system automatically depressurises after the gear is retracted
and all doors close
What is the normal sequence of EICAS gear position indications during a retraction?
Green DOWN changes to white cross-hatch during transit. When gear is up, indication changes to UP for 10 secs and then blanks.
During alternate gear extension what releases the gear doors and uplocks?
A separate dedicated DC powered electric hydraulic pump using Centre system fluid.
When the alternate gear extension system is used, does the EICAS gear indication change?
14.GEAR
Yes, to the expanded gear indications.

Do the doors close when the gear is down after an alternate selection?
No, the doors remain open.
Can the gear be retracted after an alternate selection?
Yes, the landing gear can be retracted by the center hydraulic system, if it is operating, by selecting DN then UP with the gear lever.
When is the Rudder Pedal Steering Disconnect switch used?
The switch is used during a flight controls freedom of motion check.
What provides primary steering control?
Nosewheel steering tillers for each pilot.
What is the greatest angle each will turn the nosewheel?
Up to 70d deg in either direction.
What is the maximum nosewheel deflection using the rudder pedals?
Up to 8 deg in either direction.
Is there any relationship between tiller and rudder pedal steering?
Yes, tiller inputs are summed with rudder pedal inputs
What system powers the brakes?
The electrical system via four electric brake power supply units.
How many Electric Brake Actuators (EBAs) are there on each landing gear wheel brake?
4
The EBAs are controlled by Electric Brake Actuator Controllers (EBACs). How many EBACs are there in total?
4
With RTO selected, when would the brakes be applied?
- the airplane is on the ground, and
- groundspeed is above 85 knots , and
- both thrust levers are retarded to idle
For a normal landing when will the Autobrake system apply the brakes?
- both thrust levers are retarded to idle, and
* the wheels have spun up
Which actions could disarm the Autobrake after landing?
- pedal braking applied
- either thrust lever advanced after landing
- speed brake lever is moved to the DOWN detent after the speed brakes have deployed on the ground
- DISARM or OFF position selected on the AUTOBRAKE selector.
- autobrake fault
- normal antiskid system fault
- loss of inertial data from the Inertial Reference Units (IRUs)
Where are the brake temps displayed?
Wheel brake temperatures are displayed on the GEAR synoptic display.
Where are the tyre pressures displayed?
Tire pressures are displayed inside each individual gear symbol on the GEAR synoptic.
