Landing Gear Flashcards
When do LGCIUs swap?
After full ext/ret cycle- after retraction
Which ADRs provide speed data to the safety valve?
At what speed is it locked?
ADR1+3
260kt
What valve is controlled by the Gravity Extension handle?
What aids cranking into locked position?
Do doors remain open? Can the system be reset?
Cut-off valve
Locking springs
Remain open, system can be reset with G HYD operative (normally training)
Four gear position data points?
Three data points re: cargo doors received by LGCIU?
How many flap disconnect proximity switches are there?
Up/down locked
Shock absorbers compr/extended
Doors open / shut
Bogies aligned / not
Valve
Shaft
Handle
Four
Can LGCIU 1 show position information on the three lights if failed?
So long as still electrically powered.
Which braking system stops wheel spin during retraction?
What stops wheel spin for NW gear?
Normal braking system
Brake band
Can the landing gear handle be physically moved up on the ground?
What are the conditions?
Which valves does the landing gear handle control?
What does the red arrow on the lever mean?
No, interlock system prevents lever movement.
Linked to shock absorber position and whether NW is aligned
Selector valves
Not downlocked
Wheel SD page
LG CTL amber?
UPLOCK amber?
Red triangle?
Two amber crosses?
Position disagrees with lever
Uplock engaged when gear is downlocked
In transit
LGCIU failed
What powers / controls the hydraulic steering cylinder?
What are the four conditions for pressurisation?
Yellow Hydraulic
BSCU (either channel)
- NWS pb ON
- Towing lever normal (pin)
- One engine running
- On ground
Max steering angle via the pedals?
Tiller?
By what speed do they have no effect?
What is the steering angle when lever in towing mode?
What centralises the steering on retraction?
6º (0º by 130kt)
75º (0º by 80kt)
95º
Internal cam
When is NW STRG DISC green and amber?
Green: pin and engines OFF
Amber: pin and 1 engine ON
In Alternate Braking with Antiskid, which computer controls?
Braking: ABCU
Antiskid: BSCU
What three functions does the BSCU have?
When does it swap channel?
- Checks residual brake pressure
- Monitors brake temperature
- Provides wheel speed to other systems
Swaps channel each time gear down.
When do fusible plugs blow?
900ºC
Same temperature for maintenance action on brakes
When does the antiskid kick in?
When does it deactivate?
Which ADIRUs are used?
What happens if ADIRUs fail?
Can antiskid be used with the alternate braking on Y system?
When wheel speed reaches 0.87 of ground speed
20kt
All 3 ADIRUs
If all fail, reference speed is max main landing gear wheel speed
Yes
What 3 conditions needed for Autobrake to work?
How many ADIRU, SEC?
When does autobrake engage?
Is autobrake still armed when spoilers retract?
- Green only
- Antiskid powered
- No braking failure
- One ADIRU
- Two SEC
With spoiler deployment
MAX only kicks in over 40kt
Yes, still armed
disarms after TO or Touch and Go
What is braking pressure limited to when Alternate without Antiskid?
How many accumulator applications are available?
1000 PSI- automatically by ABCU
Avoids locking / burst
7 full applications
Which hydraulic system does the parking brake use?
How long will it hold if using accumulator pressure only?
How can the accumulator be pressurised?
Yellow
Minimum 12 hours
Press Y ELEC pump
Do you need to switch the NWS/ANTISKID sw to swap braking systems?
Is differential braking still available with alternate braking?
What system is shown on the triple indicator?
No, automatic transfer to Y ALTN braking if G lost
Yes, still avail
Y system only
i.e. alternate or parking brake
measured downstream of alternate servos
What is deceleration rate with LO / MED? When will bulb light?
What do the two numbers mean next to ANTISKID on the WHEEL SD?
LO: 2 m/s²
MED: 3 m/s²
80% of commanded braking
May not illuminate in slippy conditions due to antiskid taking over, but still braking
Refer to the two BSCU channels
When does a green arc appear over brake temperatures? An amber ark?
Hottest when any exceed 100ºC
Amber 300ºC (max for TO without fans- 150 without)
What does the arrow next to the ACCU label on WHEEL pg mean?
Down if being pressurised
Up if supplying braking
No arrow if low pressure (amber)
Limitations- braking with high thrust?
Not designed for it. If performing a maintenance procedure, should be ready to reduce to IDLE if movement detected.
Max speeds with damaged / deflated tyres?
7kt (one per gear)
3kt (two per gear)
30º NWS
