Landing Gear Flashcards
what hydraulic system powers the landing gear extension and retraction
HYD SYS A
what hydraulic system powers the nose wheel steering:
- normal
- alternate
- normal = HYD SYS A
- alternate = HYD SYS B
what hydraulic system powers the brakes:
- normal
- alternate
- normal = HYD SYS B
- alternate = HYD SYS A
what alternate means exist for extending the landing gear
manual landing gear extension system (gravity)
what prevents the landing gear lever from being moved to the UP position
landing gear lever lock
what methods are used to stop the wheels spinning for retraction of the landing gear:
- main gear
- nose gear
- main gear = brakes
- nose gear = snubbers
what methods are used to hold the gear in the wheel well after retraction:
- main gear
- nose gear
- main gear = mechanical uplocks
- nose gear = over-center lock
what happens when the landing gear lever is placed in the ‘OFF’ position
cuts off hydraulic pressure to the landing gear system
what protection exists for the wheel well if a main gear is damaged and begins retracting
when a spinning tire with loose tread impacts a fitting in the wheel well ring opening, that gear stops retracting and free falls back to the down position. the affected gear cannot be retracted until the fitting is replaced
what is the purpose of the landing gear transfer unit
HYD SYS B provides the required volume of hydraulic fluid to retract the landing gear at the normal rate if:
- airborne
- engine 1 RPM below limit value
- landing gear lever = UP
- either main landing gear not up and locked
how is the landing gear normally extended
HYD SYS A releases uplocks, then falls with:
- hydraulic pressure
- gravity
- air loads
what maintains the landing gear in the down locked position
- over-center mechanical and hydraulic locks
what happens when the manual extension access panel is open
- manual gear extension is possible with the landing gear lever in any position
- normal landing gear extension is possible if HYD SYS A pressure is still available
- landing gear retraction is disabled
following a manual gear extension, what steps need to be taken in order to complete a normal retraction of the landing gear
- close manual gear extension access panel
- move landing gear lever to down with HYD SYS A pressure available
- position landing gear lever to UP
when is the nose wheel steering available
- nose gear in the down position
- nose gear compressed by aircraft weight
what happens in the event of a hydraulic leak being detected downstream of the LGTU (Landing Gear Transfer Unit)
sensor closes the Landing Gear Transfer Valve and alternate steering will be lost
what controls the nose wheel steering
- nose wheel steering wheel (capt side only)
- rudder pedals (limited)
when is the rudder pedal steering deactivated
nose gear strut extends
what does the lockout pin do
depressurizes the nose wheel steering allowing pushback
what is the brake system made up of
- normal brakes
- alternate brakes
- brake accumulator
- anti-skid
- autobrake
- parking brake
- brake temperature indication
when does the alternate braking system takeover from the normal braking system
when HYD SYS B is low or fails, HYD SYS A automatically takes over
what system is the brake accumulator pressurised from
HYD SYS B
by what system is braking pressure still available if HYD SYS A + B is lost
accumulator pressure can provide several braking applications or parking brake applications
when is antiskid available
at all times
what is the difference in the way the anti-skid operates with:
- normal braking
- alternate braking
- normal braking = provides each individual wheel with anti-skid protection
- alternate braking = provides each pair of gear with anti-skid protection