Section 7 - Airframe And Systems Description - 9 Landing Gear System Flashcards
What is the landing gear type?
Electro-hydraulic type
How is it powered?
Powered by a reversible pump
How is the pump contorlled?
Electrically, by a the LG control knob located on the LH instrument panel and by the legs position micro switches
What do the leg position micro switches allow us to detect?
Landing gear down-locked and up positions and for alerting the pilot by aural needs should the approach and landing configuration be incorrect, in terms of flaps/throttle levers/landing gear positon, in order to aviod and unintentional gear-up landing
What modes of landing gear are there?
2: normal and emergency
What does the normal operation provide?
Gear extension and retraction by means of hydraulic jacks
How is gear extension also helped?
By gravity
What does emergency operation provide?
Landing gear extension by means of a hydraulic accumulator which discharges oil in the above mentioned jacks
Where is the hydraulic oil contained?
How is it pressurized?
How does the electric pump work?
In an integrated reservoir located inside the Hydraulic Power Pack
By a reversible electric pump:
As the LG control knob is placed in either the UP or DOWN position, the pump directs the fluid through the related pressure line toward each hydraulic jack
What do we do in order to prevent inadvertent LG retraction?
The control knob must be pulled before being pushed upward for UP command
For what is the emergency hydraulic accumulator used?
Used for the landing gear extension:
normal extension line and emergency extension line converge in correspondence of the shuttle valves
Two valves:
- The first one for NLG and
- Second one for MLG emergency operation
Where is the emergency accumulator pressure indicator located?
On the tail cone, left side
How is the nitrogen pressure recharged?
On ground, a red push-button located beneath the pressure indicator allows the electrical pump for charging the accumulator should the nitrogen pressure be below the lower limit indicated on the placard
How is emergency extension controlled?
By two distributors located on the cabin floor, under a removable cover in correspondance of the pilot seat
How is the LG indication system?
Electrical
What are the main components of which the LG indication system is composed?
UP/DN limit micro-switches (6 couples, for each leg)
Leg position, 3 lights (turned ON when the pertinent leg is extended and locked and located on the LH instrument panel)
Transmition light, 1 red (turned ON during transition phases)
Pump light, 1 amber (GEAR PUMP ON caution amber light turned ON when the pump is electrically supplied )
Push to test (if installed) (for landing gear and green lights operational check)
What does each light indicate?
Three greens: illuminate only when the respective gear is down-locked
Red light: extinguishes only when all three gear legs are down-locked or they are up
Amber light: extinguishes only when the electrical pump is off
What do the Up/Down limit switches control?
LG lights lighting and pump operation on the basis of LG configuration set by the pilot through the LG control knob
What’s the push to test button?
Used to check that the landing gear position lights are operating
What is the warning horn for?
Alerts the pilot when the LG contorl knob is in UP position and at least one of the two throttle levers and/or flaps are respectively set to idle and to LAND position
What happens to LG lights during emergency extension?
LG position lights work as per normal extension mode. For this reason LG control knob must be set on DOWN position before starting the emergency procedure
IMPORTANT
What must you do after each emergency landing gear extension?
Apply the restoration procedure described in the AMM
