A320 LANDING GEAR AND BRAKES CONTROL
LANDING GEAR INDICATOR PANEL
This panel is connected to LGCIU1, which receives signals from proximity detectors.
- Green triangle light : comes on green if the gear is locked down.
- UNLK light : comes on red if the gear is not locked in the selected position.
Note: This panel is connected to the LGCIU1 only, therefore, the lights on the LDG GEAR indicator panel come on as long as the LGCIU1 is electrically supplied. If one UNLK indication remains on, the landing gear position can be confirmed using the WHEEL SD page (information from LGCIU 1 & 2). Only one green triangle on each landing gear is sufficient to confirm that the landing gear is downlocked.
LANDING GEAR SELECTOR LEVER
L/G LEVER
- UP : This position selects landing gear retraction. While the landing gear doors are opening, the normal brake system brakes the wheels of the main landing gear automatically. A brake band in the nose landing gear well brakes the nose landing gear wheels as the doors close (for aircraft equipped with nose landing gear rubbing strips).
- DOWN : This position selects landing gear extension. An interlock mechanism prevents anyone from accidentally retracting the gear while the aircraft is on the ground. It does so by locking the lever in DOWN position when the shock absorber on either main gear is compressed (aircraft on ground) or the nose wheel steering is not centered. The landing gear hydraulic system remains pressurized as long as the landing gear is extended (if green hydraulic pressure is available).
RED ARROW
- This red arrow lights up if the landing gear is not locked down when the aircraft is in the landing configuration, and a red warning appears on ECAM.
A/SKID & N/W STRG sw
ON : If green hydraulic pressure is available, then antiskid is available.
If green hydraulic pressure is lost, then:
- Yellow hydraulic pressure automatically takes over to supply the brakes
- Antiskid and nosewheel steering remain available
- Triple indicator shows yellow system brake pressure
OFF : The yellow hydraulic system supplies pressure to the brakes
- Antiskid is deactivated. To avoid wheel locking and limiting the risk of tire burst, brake pressure is automatically limited to 1000 PSI
- Nosewheel steering is lost
- Differential braking remains available through the pedals
- Triple indicator displays yellow system brake pressure
AUTO/BRK panel
The springloaded MAX, MED, and LO pushbutton switches arm the appropriate deceleration rate. The usage for each mode are as follow:
- MAX mode is normally selected for takeoff. In the case of an aborted takeoff, maximum pressure goes to the brakes, as soon as the system generates the ground spoiler deployment order
- MED or LO mode is normally selected for landing:
- MED mode sends progressive pressure to the brakes 2 s after the ground spoilers deploy in order to decelerate the aircraft at 3 m/s² (9.8 ft/s²)
- LO mode sends progressive pressure to the brakes 2 s after the ground spoilers deploy, in order to decelerate the aircraft at 2 m/s² (6.6 ft/s²).
The lighting on the pushbutton switches are as follow:
- ON light : comes on blue to indicate positive arming
- DECEL light : comes on green when the actual deceleration is 80 % of the selected rate Note: On slippery runways, the predetermined deceleration may not be reached, due to antiskid operation. In this case, the DECEL light will not come on. This does not mean that autobrake is not working.
- OFF : The corresponding autobrake mode is not armed
BRK FAN pb
- ON light : The brake fans run if the left hand main landing gear is down and locked.
- OFF : The brake fans stop.
- HOT light : Amber light comes on when the brakes get too hot and ECAM shows a caution.
BRAKES and ACCU PRESS indicator
Brake pressure is only indicated when the yellow hydraulic system controls the brake pressure. This is when the: Alternate braking system is activated, or Parking brake is applied.
ACCU PRESS : Indicates the pressure in the yellow brake accumulator.
BRAKES : Indicates the yellow pressure delivered to the left and right brakes, as measured upstream of the alternate servovalves.
PARKING BRK handle
Flight crew pulls this handle, then turns it clockwise, to apply the parking brake. The ECAM memo page displays “PARK BRK”. If the pointer is not at ON, the parking brake is not on.