Section 7 - Airframe And Systems Description - 9 Landing Gear System

Question 1

What is the landing gear type?

Answer 1

Electro-hydraulic type

Question 2

How is it powered?

Answer 2

Powered by a reversible pump

Question 3

How is the pump contorlled?

Answer 3

Electrically, by a the LG control knob located on the LH instrument panel and by the legs position micro switches

Question 4

What do the leg position micro switches allow us to detect?

Answer 4

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

Question 5

What modes of landing gear are there?

Answer 5

2: normal and emergency

Question 6

What does the normal operation provide?

Answer 6

Gear extension and retraction by means of hydraulic jacks

Question 7

How is gear extension also helped?

Answer 7

By gravity

Question 8

What does emergency operation provide?

Answer 8

Landing gear extension by means of a hydraulic accumulator which discharges oil in the above mentioned jacks

Question 9

Where is the hydraulic oil contained?

How is it pressurized?

How does the electric pump work?

Answer 9

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

Question 10

What do we do in order to prevent inadvertent LG retraction?

Answer 10

The control knob must be pulled before being pushed upward for UP command

Question 11

For what is the emergency hydraulic accumulator used?

Answer 11

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

Question 12

Where is the emergency accumulator pressure indicator located?

Answer 12

On the tail cone, left side

Question 13

How is the nitrogen pressure recharged?

Answer 13

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

Question 14

How is emergency extension controlled?

Answer 14

By two distributors located on the cabin floor, under a removable cover in correspondance of the pilot seat

Question 15

How is the LG indication system?

Answer 15

Electrical

Question 16

What are the main components of which the LG indication system is composed?

Answer 16

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)

Question 17

What does each light indicate?

Answer 17

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

Question 18

What do the Up/Down limit switches control?

Answer 18

LG lights lighting and pump operation on the basis of LG configuration set by the pilot through the LG control knob

Question 19

What’s the push to test button?

Answer 19

Used to check that the landing gear position lights are operating

Question 20

What is the warning horn for?

Answer 20

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

Question 21

What happens to LG lights during emergency extension?

Answer 21

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

Question 22

IMPORTANT

What must you do after each emergency landing gear extension?

Answer 22

Apply the restoration procedure described in the AMM