Landing Gear Flashcards
Landing Gear
How is main gear steering achieved?
Using C hydraulic system (main gear aft axle steering automatically operates when nose wheel steering angle exceeds 13o –> reduces tire scrubbing).
Which hydraulic system is used for gear retraction and steering?
• Nose gear: C/reserve hydraulic systems • Main gear: C hydraulic system.
What hydraulic system is used for normal braking?
R hydraulic system.
What hydraulic system is used for alternate and reserve braking?
C hydraulic system (if R system pressure low).
In which braking modes is anti-‐skid available?
All modes
Where are the air/ground sensors located?
Sensors located on each main gear LDG beam.
How can the ground landing gear lever lock be manually overridden?
By pushing and holding the LDG gear lever LOCK OVERRIDE switch.
Why is there no OFF selection for the landing gear lever?
LDG gear system is automatically depressurized W/ the LDG gear retracted and all doors closed.
What is the non-‐normal format for gear indication?
Expanded (non-‐normal) gear position indication (format)
How does the landing gear extend?
Gear doors open –> gear is unlocked –> gear free–falls to locked position –> all hydraulically actuated doors close –> main gear hydraulically tilted to the FLT position.
How many braces are on each main landing gear?
2 (drag brace & side brace).
What type of pump is used for alternate gear extension?
(Dedicated) DC electric hydraulic pump.
How are the gear doors affected by an alternate gear extension?
Hydraulically powered gear doors remain open.
Which hydraulic system powers the nose steering system?
C/reserve hydraulic system.
What is the steering authority for the tiller operation?
70 degrees either direction.
What is the steering authority for the rudder pedal operation?
7 degrees either direction
When will main gear steering operate?
When nose wheel angle exceeds 13o (to reduce tire scrubbing).
Which hydraulic pump provides pressure for reserve braking?
Primary C1 pump.
When will the BRAKE SOURCE light and EICAS message be displayed?
Loss of the R & C/reserve hydraulic systems.
Which hydraulic system pressurises the brake accumulator?
R hydraulic system.
Is anti-‐skid available when using only the brake accumulator pressure?
Yes
How is anti-‐skid protection achieved in alternate/reserve braking?
Antiskid protection provided to tandem wheel pairs for FWD & middle axis but individually for aft axle wheels.
When is autobrake available?
Only when normal brake system is functioning.
At what speed is RTO braking available?
Speed > 85kts.
How does the taxi brake system reduce braking sensitivity?
Antiskid system releases the brakes of one axle pair of each main LDG gear (if wheels speeds < 45kts).
Will autobrake bring the aircraft to a complete stop?
Yes.
What does the EICAS AUTOBRAKE message indicate?
Autobrake is disarmed intentionally or is inoperative.
How is the park brake set?
By depressing the brake pedals and pulling park brake lever on, then releasing the pedals (park brake can be set W/ normal or ALTN brake system pressurised, or if not pressurised, pressure maintained by the brake accumulator).
When will the BRAKE TEMP message be displayed?
Values > 5.0.
What 3 situations will cause the EICAS TIRE PRESSURE message?
• Any tire pressure ABV normal range. • Any tire pressure BLW normal range. • Any excessive pressure differences between two tires on same axle.
