systems: landing gear

Question 1

gear system description

Answer 1

hydraulically actuated
trailing link
tricycle config
strut (oil/nitrogen type)

Question 2

how gear operates

Answer 2

electrically powered hydraulic pump provides hydraulic pressure
positive hydraulic pressure holds gear UP
pressure accumulator maintains constant pressure by replacing lost pressure (prevents pump from operating continuously)

Question 3

what direction does the gear retract

Answer 3

main: inwards towards center of fuselage
nose: forwards towards the nose (airflow pushes nose gear DOWN when extended it)

Question 4

how is the gear locked down

Answer 4

downlock hooks when gear is down (springs maintain force on each hook)
hooks are released by hydraulic pressure when activating gear switch

Question 5

gear unsafe horn

Answer 5

beeps intermittently
activates when:
1) power is 20% or less AND gear is still UP
2) wing flaps are extended to LDG AND gear is still UP

Question 6

gear position lights

Answer 6

3 green: all gear DOWN
0 green, unsafe light ON: gear in transition
0 green, unsafe light OFF: gear retracted and held

Question 7

squat switch

Answer 7

one on each main gear
activates with weight
left: prevent gear retraction
right: stall warning heat OFF, allows glow plugs to activate, prevents TACH from counting, disables traffic alerting system

Question 8

emergency gear extension

Answer 8

manual gear extension
relieves all hydraulic pressure from system (bypasses pump)
gravity force gear down, hooks and springs keep it locked