Landing Gear Flashcards
What is the overcentre link responsible for?
The mechanical locking of the main gear down.
What does PSEU stand for? What are its functions?
Proximity Sensor Electronics Unit.
The PSEU controls the sequencing of landing gear and hydraulically operated gear doors during the undercarriage extension and retraction process.
What does the PSEU monitor?
Gear up-locks Gear down-locks Gear doors Wt on wheels Pax/baggage door positions
Are the gear doors mechanically or hydraulically controlled?
The door the gear is held in is mechanically controlled. The other doors (centre and rear for main gear and forward for for nose gear) are hydraulically controlled.
Is the main gear extension electrically, mechanically or hydraulically controlled?
An electrical signal is sent to the PSEU when the gear is selected down. The mechanical up-locks are then hydraulically broken and the gear is hydraulically lowered by the main gear actuators.
What does the ‘LDG GEAR INOP’ caution light indicate to the pilot.
After retraction indicates gear door sequence failure. Emergency extension required, normal extension may force gear through closed doors.
After extension door sequence valve failure. Do not try to retract the gear.
If required, what is the second way to verify the gear is down and locked? What is the consideration when using this indication?
Down-lock verification indication lights activated by a switch located in the emergency nose wheel extension door.
The taxi light needs to be off.
What does opening the main and nose emergency extension doors do?
Opening the main door allows the system to bypass the normal extension hydraulic circuit.
Opening the nose door allows hydraulic fluid to be redirected for alternate gear extension.
What scenarios would require an alternate landing gear extension,
Gear is selected down, but it doesn’t show down and locked
Gear is selected down and the LDG GEAR INOP caution light illuminates,
Gear may not show down and locked,
Loss of fluid to the number 2 hydraulic system.
What are the 2 cases that will cause the landing gear warning horn to sound? Which case may be muted?
Landing Gear not down and locked, flap 15 or more, Auto feather system off, both power levers below take off setting
Landing gear not down and locked, one or both power levers at or near flight idle, IAS below 130.
Case 2 may be muted if one power lever is advanced.
If Nose wheel steering is U/S or switched off, what does the nose wheel revert to?
A shimmy dampened castoring wheel. (up to 120 degrees left and right)
When might the NOSE STEERING caution light illuminate? Where can you find performance on taking off with Nose wheel steering inop?
Failure of ECU circuitry
Fault in the Hydraulic inputs.
OM2A had guidance on performance with abnormal configurations including Nose wheel steering inop.
Is reverse steering approved?
No
Following any landing gear retraction or extension not covered by a specific procedure in the AFM, what should the pilot do?
Conduct the Alternate Landing Gear Extension Procedure.
