Landing Gear Flashcards
Landing Gear
A
Landing Gear
Tricycle-type configuration
Retractable
Electrically activated
Hydraulically actuated
5
2
Q
How is the landing gear extended and retracted?
A
How is the landing gear extended and retracted?
Electronically commanded and hydraulically act
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3
Q
When will the aural warning for the landing gear sound?
A
When will the aural warning for the landing gear sound?
If the gear is not down and locked and:
- Below < 700’ RA and low TLA (45o both ENGs, 59o OEI) or
- ## Any altitude with flaps ≥ 5
4
Q
Can the landing gear aural warning be silenced by pushing the LG WRN INHIB button?
A
Can the landing gear aural warning be silenced by pushing the LG WRN INHIB button?
Only if both RAs have failed and flaps are between 0 and 4. flaps 5 or full cannot be silenced
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5
Q
What are the 3 landing gear extension modes?
A
What are the 3 landing gear extension modes?
1. Normal
2. Electric Override (Bypasses PSEM to directly command selector valve)
3. Alt Gear Extension, free fall method, release hydraulic pressure and unlocks open
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6
Q
What is the purpose of the DN LOCK RLS button on the landing gear lever?
A
What is the purpose of the DN LOCK RLS button on the landing gear lever?
- Mechanically releases the landing gear lever lock
- Lock protects against inadvertent landing gear retraction when WoW
7
Q
What keeps the gear locked in position?
A
What keeps the gear locked in position?
Extended = Downlock springs
Retracted = Uplock hooks
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8
Q
Describe the landing gear indications?
A
Describe the landing gear indications?
1. Green = Down and locked
2. White = Up and locked
3. Amber = In Transit
4. Red = Gear Position & Lever disagreement (after 20 secs)
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9
Q
How do the landing Gear doors actuate?
A
How do the landing Gear doors actuate?
Mechanically, during landing gear extension or retraction
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10
Q
How are the brakes commanded?
A
How are the brakes commanded?
1. Brakes by Wire (elec. cmd, hyd actuated)
2. Pedal position transducers send brake requests to the Brake Control Module (BCM)
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11
Q
What hydraulics systems provide brake pressure?
A
What hydraulics systems provide brake pressure?
Hyd 1 = Outboard brakes
Hyd 2 = Inboard brakes
Hyd 1/2 = Emer/PB
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12
Q
What protections are provided for braking?
A
What protections are provided for braking?
1. Touchdown (no braking until 3 secs or > 50 kts wheel speed
2. Locked wheel (allows up to 33% differential braking for steering purposes)
3. Anti-skid (compares wheel speeds and releases pressure)ions less than 10 kts
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13
Q
Below which speed does anti-skid stop working?
Below what speed does locked wheel protection stop working?
A
Below which speed does anti-skid stop working?
Below 10 knots
Below what speed does locked wheel protection stop working?
Below 30 knots
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14
Q
How many applications will the parking brake/emergency brake provide?
A
How many applications will the parking brake/emergency brake provide?
6 applications
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15
Q
What are the limits for nosewheel steering?
A
What are the limits for nosewheel steering?
Angle varies with groundspeed
10 knots up to 76 degrees
26 knots up to 20 degrees
27 to 100 knots maximum 7 degrees
0ver 76 degrees it goes freewheeling
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16
Q
What stops the wheels from spinning during retraction?
A
What stops the wheels from spinning during retraction?
Main gear = BCM applies brakes after W-off-W
Nose gear = Snubbers in the nose bay stop the wheels
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17
Q
How does the alternate gear extension work?
A
How does the alternate gear extension work?
1. You press the button on the top of the alt. gear lever that allows
it to be actuated
2. Pull the handle up
3. Opens Free-Fall Selector Valve, depressurizes the landing
gear hydraulic lines and releases all gear uplocks
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18
Q
How does the electric override for the landing gear work?
A
How does the electric override for the landing gear work?
1. You move the switch from the Normal to Gear Down position
2. This bypasses the Proximity Sensor Electronic Module (PSEM) and goes direct to LG Selector Valve to open FWD and AFT Gear Doors and extend the gears
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19
Q
What are the 2 Autobrake Modes?
What 4 actions cancel the Autobrakes?
A
What are the 2 Autobrake Modes?
1. Landing (Lo, Med, Hi)
2. RTO
What 4 actions cancel the Autobrakes?
1. Autobrake selector knob to OFF position
2. Brake Pedals are applied (wheel speed above 60 kts if RTO selected)
3. Brake Control System Failure (while below 60 kts if RTO selected). RTO is not activated below 60 knots.
4. Either thrust lever applied beyond idle during autobrake application
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20
Q
How many WoW Sensors are there and what monitors the WoW Sensors?
How many uplock and downlock sensors sense gear locked position?
A
How many WoW Sensors are there and what monitors the WoW Sensors?
6 Wow Sensors monitored by 2 PSEMs that send signals to Mau1
and Mau3
How many uplock and downlock sensors sense gear locked position?
2 uplock and 2 downlock sensors total of 12
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21
Q
Brake wear can be monitored through what?
A
Brake wear can be monitored through what?
Brake Wear Pins located on each main wheel. when pin is flushed, MX must be notified for brake change. 4 pins on each main wheel for a total of 8.
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22
Q
What are the 4 functions of the 2 BCMs and 1 ABM?
A
What are the 4 functions of the 2 BCMs and 1 ABM?
1. Locked Wheel
2. Anti-skid
3. Touchdown
4. Autobraking
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23
Q
How many brake applications do the emergency brake pressure accumulators permit?
A
How many brake applications do the emergency brake pressure accumulators permit?
6 full, good applications and then you’re out of brakes. no locked Wheel, Anti-skid or Touchdown protection provided.
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24
Q
What are fusible plugs on the wheels used for?
A
What are fusible plugs on the wheels used for?
They melt which relieve tire pressure in case of tire overheating
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25
Q
What happens if the nose-wheel exceeds 76o?
A
What happens if the nose-wheel exceeds 76o?
Reverts into free-wheel mode
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26
Q
Free Wheel Steering Mode
A
Free Wheel Steering Mode
Auto activated when:
Air/ground system failure occurs
Steering angle > 76°
Steering system failure
2 ways to disconnect the steering
Disconnect switch on yokes
Disconnect switch on GPU access panel
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27
Q
How is the alternate landing gear extension powered?
A
How is the alternate landing gear extension powered?
Mechanically powered, gravity actuated
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28
Q
Are the brakes depressurized during flight?
A
Are the brakes depressurized during flight?
Yes
1. 10 seconds after liftoff
2. gear handle in up position
3. Wheel speed 0
