Landing Gear and Brakes Flashcards
How is the landing gear extended and retracted?
Electrically commanded
Hydraulically actuated
When will the aural warning for the landing gear sound?
If the gear is not down and locked, and less than 700ft RA and low TLA. OR Any altitude with flaps set greater than 5.
Can the landing gear aural warning be silenced by pushing the ‘LG WRN INHIB’ button?
Only if both radio altimeters have failed
What are three landing gear extension modes?
Normal: LG lever DOWN
Electric Override Valve: Bypasses PSEM to directly command selector
Alternate Gear Extension: Manual uplock release opens free-fall sequencing valve
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 weight-on-wheels.
What keeps the gear in the locked position?
Extended – Downlock springs
Retracted – Uplock hooks
Describe the landing gear indications
Green: Down and locked
White: Up and locked
Amber: In transit
Red: Gear postition and lever disagreement (20 second period)
How do the landing gear doors actuate?
Mechanically, during landing gear extension or retraction
How are the brakes commanded?
Brake by Wire.
Electrically commanded and hydraulically actuated.
Pedal position transducers send brake requests to the BCM (Brake Control Module)
What protections are provided for braking?
Touchdown: No braking until 3 seconds or greater than 50knts. wheel speed after touchdown.
Anti-skid: Compares wheel speeds and releases pressure (inop less than 10knts)
Locked-Wheel: Allows up to 33% differential braking for steering purposes (inop less than 30 knts)
How many applications will the parking/emergency brake provide in a HYD 1 and 2 failure?
6 applications
What stops the wheels from spinning during retraction?
Main gear: BCM applies brakes after weight off wheels.
Nose gear: Snubbers in the nose bay stop the wheels.
Which hydraulic system controls the nosewheel steering?
HYD 2
What hydraulic system(s) provide pressure for brakes?
HYD 1: Outboard brakes.
HYD 2: Inboard brakes.
HYD 1 and 2: Parking/emergency brake
