Chapter 7: Landing Gear Systems

Question 1

what does main and nose landing gear do?

Answer 1

main: main support of large download forces, brakes installed here

nose: support weight and steering mechanism

Question 2

3 types of landing gear configuration

Answer 2

1) tail/conventional
2) tandem
3) tricycle

Question 3

tail/conventional configuration is used?

Answer 3

older aircraft on rough field ops

Question 4

tricycle configuration is used due to?

Answer 4

1) more forceful brakes without nosing over, higher landing speed
2) better visibility from flight deck
3) prevent ground-looping of aircraft (a/c CG forward, keeps a/c moving forward)

Question 5

what are aircraft wheels used for and material made?

Answer 5

support entire weight of aircraft

lightweight, strong alu alloy

Question 6

function of aircraft tyres

Answer 6

1) supporting weight
2) absorbing shock
3) gripping contact with runway
4) discharge static electricity

Question 7

what does a trunnion do?

Answer 7

allows gear to pivot during retraction and extension

Question 8

what is a strut?

Answer 8

vertical member of the landing gear assembly

Question 9

purpose of drag link/strut

Answer 9

provide support to shock strut and stabilise shock strut longitudinally

Question 10

purpose of side strut/ brace link

Answer 10

stabilise landing gear laterally

Question 11

purpose of overcenter link

Answer 11

prevent link from pivoting at joint except gear retracted > prevent collapse of gear during ops

Question 12

how does overcenter link work?

Answer 12

locks the main gear only in the down position

Question 13

what does a lock mechanism do?

Answer 13

“downlock” locks LG in down position, main LG is held up in by uplock mechanism

Question 14

what does the axle do?

Answer 14

main wheels are supported and installed

Question 15

how does non-shock absorbing LG work?

Answer 15

flexible struts that receives impact of landing and return it to airframe to dissipate at slower rate (gear flexes initially)

Question 16

what fluid is used for shock absorbing LG?

Answer 16

nitrogen gas combined with hydraulic fluid

Question 17

what are the upper and lower chamber filled with in the shock absorbing LG?

Answer 17

upper: nitrogen gas
lower: hydraulic fluid

Question 18

what happens when LG is set to UP position?

Answer 18

1) unlock & open wheel well doors
2) unlock LG from downlock
3) retract LG
4) close doors
5) LG kept UP by uplock mechanism

Question 19

what happens when LG is set to DOWN position?

Answer 19

1) unlock & open wheel well doors
2) unlock uplock
3) extend LG
4) close wheel well doors

Question 20

Power Formula

Answer 20

W = PQ / η

Question 21

what does the downlock mechanism do?

Answer 21

prevent retraction of LG when in DOWN position

Question 22

how can the aircraft be steered?

Answer 22

nose wheel steering / differential braking

Question 23

what does the cam assembly do in the LG system?

Answer 23

keep gear align, line up wheel and axle assembly in straight position, align with longitudinal axis

Question 24

what does a shimmy damper do?

Answer 24

control nose wheel shimmy through hydraulic damping

nose gear tend to oscillate at certain speeds

Question 25

how does emergency extension system work?

Answer 25

handle is pulled > releases uplock & allows gears to freefall to extended position by gravity

Question 26

what does a safety switch do on the LG system?

Answer 26

positioned to open/close depending on extension/compression of main LG strut

Question 27

what is a ground lock?

Answer 27

pin placed into holes of the gears to prevent it from collapsing

red tags attached to them “remove before flight”

Question 28

what do the lights on gear indicator mean?

Answer 28

green: down and locked
red: in transit
no light: up and locked

Question 29

what does a warning horn do?

Answer 29

sound off when LG is not down & locked when landing

Question 30

what does a torque link do?

Answer 30

keep the wheels aligned

Question 31

what are 2 indications that the LG is not safe?

Answer 31

1) red light in LG indication
2) warning horn