Landing Gear Flashcards
How is the gear held up?
Mechanical uplocks
How are the landing gear bay doors opened?
Mechanically
How is the gear held down?
Downlock springs
What are the 3 ways to extend the gear?
- Normal - via gear handle
- Electrical override - electrical signal bypasses the PSEM
- Alternate - residual hydraulic pressure releases uplocks and gear free falls
What must you do to get 3 green indication using the alternate gear extension?
Place the gear handle in the down position
If the down/uplock sensors disagree, which one will be considered valid?
The one that agrees with the landing gear lever position
Which hydraulic system provides pressure to the outboard brakes?
Hydraulic system 1
Which hydraulic system provides pressure to the inboard brakes?
Hydraulic system 2
If both hydraulic systems fail, is there a way to stop the airplane?
Yes, via the emergency parking brake
What are some functions of the brake control modules (BCM)?
- Locked wheel protection
- Anti-skid protection
- Automatic wheel braking
- Touchdown protection
When is locked wheel protection active?
Above 30 kts
When is anti-skid deactivated?
Below 10 kts
When is anti-skid not available?
For the emergency parking brake system
What prevents the main landing gear from being retracted with the wheels spinning?
Automatic wheel braking
What is touchdown protection?
Prevents the airplane from touching down with the main landing gear brakes applied
When is touchdown protection deactivated?
- 3 seconds after WOW has sensed the ground or
* Wheel speed above 50 kts
What supplies the emergency/parking brake?
Hydraulic system 1 and 2
Where are the pressure accumulators for the emergency/parking brake system?
Isolated from both normal hydraulic systems
How many brake applications are available from the accumulators?
6 full brake applications
What supplies the nose wheel steering?
Hydraulic system 2
Handwheel steering angle
- 76° until 40 kts
* Decreases to 7° at 100 kts
What is the maximum rudder pedal steering angle
7°
When is free wheel steering automatically activated?
- Air/ground system failure occurs
- Steering angle > 76°
- Steering system failure
What are the two ways to disconnect the free wheel steering?
- Disconnect switch on yokes
* Disconnect switch on the external power connection
How many weight on wheels (WOW) sensors are there?
- 6 total
* 2 on each wheel
When will you get a green towing light?
- Steering disengaged
- Parking brakes not applied
- Main brakes not applied
How many downlock/uplock sensors are installed?
- 12 sensors total
* 2 uplocks and 2 downlocks per landing gear
When will the gear warning sound and can not be silenced?
•Flaps 5 or full regardless of thrust lever or radio altimeter
Flaps 0 thru 4
•RA below 700 ft AGL and
•Either thrust lever below 45° for 2 engines
•Thrust lever below 59° for 1 engine
In the event of a dual radio altimeter failure when will the inhibit button silence the aural warning?
Only when flaps are between 0-4 positions
How are the brakes operated?
Brake by wire
Describe the landing gear indications
- Green - down and locked
- White - up and locked
- Amber - in transit
- Red - gear position and lever disagree
