32 - Landing gear Flashcards
What is the primary method for extending the landing gear on the A320?
Hydraulic actuation (provided by Green hyds)
What triggers the LGCIU control to switch?
LGCIU control changes each L/G cycle. L/G control lever moved to UP (retraction of the gear) will trigger the opposite LGCIU to take control.
How is the L/G locked down, after a free fall extension?
If hyd PX unavailable, the gear is held down by springs and mechanical locks.
What hyd system controls NWS?
Yellow
What shows on the Triple PX indicator, when green system (normal) is in control?
Nothing triple indicator only works when fed by yellow hyds. (Altn brks)
What is meant by ‘brake by wire’?
Green (normal) is a brake by wire system. Whereas yellow is direct hydraulic input from the pedals, controlled by the ABCU.
What would cause Anti skid loss?
A/Skid + N/WS switch toggled off.
BSCU failure
Low PX Green and Yellow hyds.
If there is yellow and green hyd failure, how is braking achieved?
Accumulator (7 full brake pedal presses, should be available)
How long should the triple px indicator Accu px hold if in the green band?
12 hrs
What conditions need to be active for NWS to operate
Atleast 1x ENG MSTR switch on
NWS disconnect pin NOT fitted.
A/Skid + N/WS switch toggled ON.
A/C WOW
What happens if both steering hand wheels are operated?
Algebraically summed.
What does the pedal disconnect button on steering handwheel do? And when would it be operated?
Disconnects NW/S from the pedals, pilots do this to perform full and frees. (To achieve full rudder deflection)
What N/wheel deflection can be achieved by the handwheel?
74degrees. (Tiller only works up to 80KTS)
What rudder deflection can be achieved by rudder pedals when NWS is engaged?
6degrees (Angle decreases to 0degrees at 130kts during taxi. NWS disconnects after this speed)
How is Nose wheel position sensed by the BSCU?
RVDTs on the Nose L/G are used as feedback sensors
What indications do pilots get when Nosewheel steering pin is in?
NWS disc on ECAM
Amber caption when 1x eng running.
Green when eng not running.
How would you reset the BSCU?
A/Skid + N/WS switch cycle.
Which 2 items are optional extra components for wheels?
TPIS
Brake Fan (Manually operated by cockpit P/BSW 402VU LDG GEAR BRK panel)
What is the L/G logic sequence for extension?
L/G selected down
Doors open
Gear down
Doors closed.
Commanded by LGCIU, feedback provided by prox switches.
How and when is the gear safety valve triggered in flight?
Above 260KTS, hyd lines are depressurised. (To stop gear dropping in excessive speed) triggered by info from ADIRU 1&3.
If a leak occurs in the bottom of the shock absorber of the MLG, how can this be fixed?
By activating the spare seal valve.
How are brake line leaks managed?
Hydraulic fuses. (Fitted in the normal and alternate hyd lines.)
What is the centring cam for and where is it located?
Nosewheel, for alignment and centring during gear retraction
Purpose of the lock stay assy?
Provides an overcentre stop and geometric lock to keep the landing gear stable and extended.
What are DDV’s?
Direct Drive Valves (commanded by the ABCU in alternate braking)
Autobrake can be disarmed by applying sufficient pressure to footbrakes.
True or False?
True. (Think sidestick logic.)
In an emergency how is accumulator px used to maximum efficiency?
The ABCU inhibits the antiskid protection and maintains a
predetermined level of braking regardless of pedal position.
When is BSCU control switched?
Every L/G extension
BTMU (brake temp monitoring) is fitted as standard, but is it necessary?
Both may be inop if brake-cooling time is applied.
How would you deactivate a brake pack for dispach?
disconnect the self sealing coupling
what should be considered before pulling LGCIU CB’s
Linked to many systems, could cause multiple secondary faults. Flight config precautions must be taken into account.
How can a levelling procedure via the ADIRUs be performed?
Jack A/C
Align IR
Alpha call ups for PITCH and ROLL
If using a spirit level for A/C levelling, where do you put the spirit level?
FWD cargo compartment
What’s the max towing angle?
95 degrees
