Term
| Which hydraulic system powers the landing gear, nose wheel steering and brakes? |
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Definition
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Term
| What is the tire pressure of the main landing gear? |
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Definition
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Term
| How are the main landing gear locked up? Down? |
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Definition
Uplocks: mechanical locks
Downlocks: locking mechanism within MLG actuator |
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Term
| What is the function of the proximity sensors? How many are there? |
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Definition
There are 2 sensors in each gear
Prevent gear retraction on ground
Determine "ground" and "air" status |
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Term
| How is the nose landing gear locked up? Down? |
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Definition
Uplocks: mechanical locks
Downlocks: overcenter locking brace |
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Term
| When is the aircraft in "ground" mode? "Air" mode? |
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Definition
Ground: 3 out of 4 MLG proximity sensors detect WOW
Air: not in ground mode |
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Term
| What are the 3 primary functions of the PSEU? |
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Definition
Proximity Sensing Electronic Unit
Electrically controls landing gear
Sends "ground" and "air" status to systems
Arms/disarms anti-skid and NWS |
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Term
| How does alternate extention of the gear work? Hint: uplocks and dump valves |
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Definition
Pulls 4 uplocks: nose gear doors, nose gear, and both main landing gear
Opens 3 dump valves: nose gear doors, nose gear, and main landing gear |
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Term
| How is the nose door locked during an alternate extension? |
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Definition
2 downlock assist actuators
Airflow |
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Term
| How is the main landing gear locked during an alternate extension? Without system #2? |
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Definition
2 downlock assist actuators (HYD SYS 2) force MLG actuators to full extension and engage downlock mechanism
(without HYD SYS 2, side slip) |
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Term
| When is the landing gear horn activiated (all systems normal)? |
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Definition
Weight off Wheels for > 2 minutes and gear not down and locked when < 1000' VSI > 400 fpm
<500' throttles idle or flaps > 30° |
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Term
| When is the nose wheel steering activated? |
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Definition
Nose wheel steering ARMED
HYD SYS 3 pressurized
NLG down and locked
"ground" mode |
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Term
| What are the limits of the nose wheel with the tiller? Rudder? |
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Definition
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Term
| How is the nose wheel steering centered after takeoff? |
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Definition
Electronically by the ECU (Electronic Control Unit)
Mechanically by centering cams |
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Term
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Definition
| Fault, Manually disarmed or Free-castering mode |
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Term
| Which hydraulic systems operate the brakes? |
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Definition
Inboard: HYD 3
Outboard: HYD 2 |
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Term
| How many fusible plugs are on the aircraft? |
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Definition
| Each main wheel has 4 fusible plugs |
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Term
| How is main wheel rotation stopped after takeoff? |
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Definition
| Hydraulic pressure from the nose gear is directed to the MLG brake control valves |
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Term
| Approximately how many brake applications are provided by the accumulators? |
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Definition
| 6 brake applications with the anti-skid off |
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Term
| What is the precharge pressure of the brake accumulators? |
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Definition
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Term
| How does the loss of HYD 2 or 3 affect braking capabilities? |
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Definition
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Term
| How do the wear indicator pins work? |
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Definition
2 pins on each brake
Checked with brakes applied
HYD SYS 2 & 3 must be pressurized |
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Term
| What does the ASCU measure? |
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Definition
Anti-skid Control Unit
Senses rotational and rate of deceleration
Compares speed of paired wheels |
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Term
| When is the Anti-Skid "ARMED"? |
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Definition
Parking brake is not engaged
Both MLG are down and locked |
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Term
| When is the Anti-Skid system operational? |
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Definition
35 kt spin up or
WOW signal after 5 second delay |
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Term
| What is the minimum speed that the Anti-Skid is operational? |
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Definition
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Term
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Definition
| Nose doors are open 10 seconds after gear is locked or airspeed > 250 kts |
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Term
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Definition
| One or more sensors disagree after 20 seconds |
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Term
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Definition
| One of the critical drivers (there are 18) is not functioning |
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Term
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Definition
| One of the non-critical drivers (there are 10) is not functioning |
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Term
| What is possible if, while single engine, the landing gear is in transit and a large flight control demand is made? |
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Definition
| Priority valve closes and hydraulic fluid is temporarily cut off from the landing gear |
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Term
| Where is brake pressure readout displayed? |
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Definition
Hydraulic synoptic page
EICAS Summary page |
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