A330 Landing Gear PDF

# A330 Landing Gear ## ATA 32 Landing Gear - **Each main landing gear** - Four wheels, twin tandem boogie assembly - Oleopneumatic shock absorber - Each wheel fitted with anti-skid brake. - **Shortening mechanism** reduces main gear length by retracting the shock absorber into the mai...

# A330 Landing Gear ## ATA 32 Landing Gear - **Each main landing gear** - Four wheels, twin tandem boogie assembly - Oleopneumatic shock absorber - Each wheel fitted with anti-skid brake. - **Shortening mechanism** reduces main gear length by retracting the shock absorber into the main leg during retraction. - **Hydraulically operated pitch trimmer** on each boogie - Damps movement and ensures return to normal position after lift off. ## Nose Landing Gear - Two wheel nose gear strut - Oleopheumatic steering system - Retracts forward to the fuselage. ## L/G Doors and Operation - Gear and door sequencing is electrically controlled by the LGCIU's. - Each LGCIU switches over after one complete gear cycle: - At each 4G retraction. - Or in case of a failure. - **All gears and doors** are hydraulically actuated by the green hydraulic system. - **Safety valves isolate hydraulic supply** above 280kts. - **Landing gear position indicators** on center panel are provided by LGCIU 1 (even if LGCIU 2 is controlling gear cycle). ## Landing Gear Gravity Extension - Gravity extension system is an electro-mechanical system located in the center instrument panel. - When the electrical selectors are set to down: - L/G hydraulic system is isolated by the cut-out valve from the green system. - Main and nose landing gear doors and gear unlock. - Main and nose landing gears extend by gravity. - Locking springs assist by downlocking. - Main and hose landing gear doors remain open. - After free fall operation: - It is possible to restore normal operation provided the green hydraulic pressure is available. - If L/G gravity extension: - No nosewheel steering ## L/G Selector Lever - Two position selector with electrical signals to 2 LGCIU - **UP** - Retraction Selected. - During gear doors open, main landing wheels are auto braked. - Nose landing wheels are braked by brake band in the bay. - **DOWN** - Interlock mechanism prevents unlate retraction of L/G by locking the lever in "Down" when. - Both M/L/G shock absorbers are compressed. - N/L/G is not fully extended on ground and NW is not in center position. - **Red Arrow** with ECAM warning in approach at 750 ft RA if L/G not downlocked in landing config. ## L/G Gravity Extension - Selector guard open - **DOWN** - 2 motorized actuators are electrically powered to close the hydraulic cut-off valve and to disengage door and gear uplocks which permit the nose gear and main L/G to deploy by gravity and to automatically lock down. ## General - **Normal brakes** - Green Hyd. - **Alternate brakes** - Blue Hyd. - **Accumulator** - Blue Hyd. - **Dual Channel BSCU** controls all braking modes and functions (Normal Braking, Alternate braking, Autobrake, Antiskid). - **BSCU channel selection** changes at each L/G down failure of a BSCU. - **Main L/G has fusible plugs** against five burnt. - **Main gear brake cooling fans**. ## Anti-Skid - At skid brake release orders are sent to: - Normal servo valves. - Alternate servo valves. - ECAM system to show released brakes. - **Without auto brake** full braking performance is only achieved at full pedal deflection. - **Antiskid deactivates be 10kt (9/5)**. Antiskid is only operative during hard braking. - **Antiskid compares ML/G speed with A/F speed reference.** - When speed decreases below 0.88 reference speed. - Brake release orders are given. - If Adiru's fail vet speed = (maximum of either L/G horizonta) - Normal ops reference speed, BSCU gets the ADIRY 1/2/013 horizontal acceleration from ADIRY 1/2/013. ## Autobrakes - **ARMING** LO/MED/MAX Conditions: - Green hyd. pressure available. - Anti skid electrically powered. - No failure in braking system. - At least 2 PRIMS available and able to command ground spoilers. - At least one Adiru. - **Autobrakes activates** - At the command of ground spoilers extension. - LO/MED - ground spoilers extend and speed > 40kts when mode kicks in. - MAX mode - **But** Below 72kts autobrakes wont activate cause ground spoilers wont extend. - **Autobrakes disarm** - Repressing the brakes pb. - Loosing arming condition. - Applying sufficient deflection to at least one brake pedal when auto brakes active. - After take off or touch and go. ## Operation - **Normal Braking** - Antiskid operative - Auto brakes available. - **Brakes normal when** - Green hyd. pressure. - MLG on ground condition. - A/skid N/W STRG switch on. - **Normal braking achieved via**: - **Pedals** - **Automatically** - **No brake pressure indication** autobrake on ground. L/G lever up in flight. - **Alternate braking with Antiskid** - Autobrakes not operative - Active when: - G HYD pressure insufficient and - BLUE HYD pressure available. - Antiskid N/W Switch ON. - Parking brake not ON - ALT Braking active in flight when L/G lever is up. ## Automatic Switching to Alternate Braking - Automatic switching to alternate braking is achieved by an auto hydraulic selector. - BSCU controls atten antiskid via alternate servo valves. - **Brake and accumulator pressure is indicated on the triple indicator**. - **Initial brake force is higher on alternate brake than normal mode**. ## Alternate Braking without Antiskid - Autobrakes and antiskid inoperative. - **Antiskid Deactivated**: - Electrically (A/SKID N/W ST SW off OR power supply failure OR BSCU failure). - Hydraulically (B + G low pressure. Brakes supplied by brake accumulator only). - **Pilots must modulate brake pressure at or below 1000 PSI to avoid wheel locking.** ## Accumulators - Accumulators are designed to supply 7 full bake applications. ## Parking Brake - Brakes supplied by blue hydraulic system. - Accumulator pressure - 12 H (Parking brake) - If Park brake activated and no blue hydraulics or accumulator not available normal braking can be applied via brake pedals. - **ON** - If green HYD available. - Anti skid / Nose wheel available. - **IF** Green pressure lost: - Blue system takes over brakes (displayed on hiple indicator). - Antiskid available. - No nose wheel steering. - **OFF** - Alternate, Blue Hydraulics. - Braking with no antiskid and no nose wheel steering. ## Auto Brake Panel - **LO/DECEL ON** - **Push buttons arm** LO/MED/MAX deceleration rates. - **MAX** - Selected for take off. - Max pressure goes to brakes as soon as ground spoilers deployment order. - **MED/LO** - Selected for landing. - **LO** - Progressive pressure 1 second after ground spoiler deployment order. - Decelerate A/C at 1.8 m/s2. - **MED** - Progressive pressure at ground spoiler dep order. - Decelerate A/C at 3.0 m/s2. - **ON DECEL** - Shows positive arming. - When autobrake is active and the A/C deceleration rate corresponds to the rate. - LO/MED - 80% of selected rate. - Med rate - 2.65 m/s2. - MAX - - **Slippery runway DECEC might not appear even when decerlerating.**