LANDING GEAR Flashcards
(37 cards)
What controls the landing gear extension/retraction and nose-wheel steering?
Two Landing Gear & Steering Control Units (LGSCU)
What system controls the brakes?
Two Brake Data Concentrator Units (BDCU) and four Electric Motor Control Units (EMCU)
Which Hydrailic system provides pressure for gear extension & retraction?
HYD SYS 1
Does the retraction actuator stay pressurized in the extended position?
Yes, but not in retracted position
In what mode does the two LGSCU operate?
Active/active. They operate at the same time for the landing gear control function.
In what mode does the LGSCU operate in for nose wheel steering?
Active/standby. Changes roles at each flight.
How many proximity sensors for each lang gear?
Four. Two for up detection and two for down.
What is the Alternate Extension?
Backup for the normal extension. Powered by the DC ESS BUS 3. Releases the unlock hooks and allows free-fall landing gear extension.
What is the Alternate Extension dormancy check?
At the next extension after each 550 flight hours, the LGSCU does an alternate extension instead of a normal extension.
When can the “GEAR” aural warning not be muted?
Any landing gear not down and locked
RAD ALT detects less than 1000’ AGL
Rate of descent is more than 250’/min for 3 seconds (latched)
The SLAT/FLAP lever is set to a landing position and
One of the conditions that follow occurs:
Both thrust lever angles are set to approach with both engines operative, or
Single thrust lever angle is set to approach
When can the “GEAR” aural warning be muted?
The landing gear is not down and locked
All radio altimeters have failed
Both thrust levers are set to approach
The SLAT/FLAP lever is in the landing position, and
Pressure altitude is below 15,000’.
Which hydraulic system provides pressure for the nose wheel steering?
HYD SYS 2 provides pressure to the steering motor, which drives a rack and pinion gear to turn the nose landing gear.
How many degrees will the tiller turn the nose wheel?
80 degrees either side of center. Intended for low speed taxi and maneuvering in the ramp area. Tiller is automatically centered by a spring and its movement is damped to avoid over travel and to be more representative of nose wheel motion.
What are the steering wheel limitations as a function of speed?
Ground speed less than 30 knots: there is no reduction. Tiller controls nose wheel up to 80 degrees either side of center
Ground speed between 30 knots and 100 knots: proportional reduction. As ground speed increases steering decreases automatically from 80 degrees to 9 degrees either side of center.
Ground speed greater than 100 knots: maximum reduction. Tiller controls nose wheel is limited to 9 degrees.
How many degrees does the rudder pedals give you?
9 degrees. Intended for high speed taxi, take off and landing rollouts
What does the Red TOW/NO TOW light indicate?
Nose wheel steering is active and or if any braking force is applied to the brakes.
How many degrees of nose wheel travel with the nose-wheel steering system disconnected?
130 degrees either side of center without disconnecting the torque links.
What does the rudder pedals disconnect switch do?
Disconnects the rudder pedals from the steering system so that ground rudder checks can be done.
When will the wear data for brakes show?
When there is less than 55 of brake life remaining. Equivalent to less than 100 landing.
What does the wheel speed transducer do?
Transmits wheel speed information for the operation of the anti-skid system and spoiler actuation.
What is the over pressure limit?
400psi. Over-inflation protection plug
What is the over temperature limit?
200*C. 3 fusible plugs installed on the brake side of each main wheel to release tire pressure.
How many Electric Motor Actuators?
4 EMAs. Also calculates brake wear
Which system provides power to the EMAs?
28VDC from the ESS 1 & DC ESS 2
