NORMAL BRAKINGNormal braking is obtained when:- The green hydraulic pressure is available,- The Anti/SKID and Nose/Wheel Steering control switch is in the ON position,- The Parking Brake control switch is in the OFF position.Electrical control is obtained:- Through the pedals,- Automatically on the ground by the auto brake system,- In flight when the gear control lever is set to UP (in flight braking).ALTERNATE BRAKINGThe alternate brake system is powered by the yellow hydraulic system and backed up by a brake accumulator.The Alternate Braking Control Unit (ABCU) electrically controls the alternate braking. The ABCU becomes active when the normal brake system is faulty and/or low hydraulic pressure is detected in the green system. Braking inputs are given by the brake pedals and transmitted through the Alternate Brake Pedal Transmitter Unit to the ABCU, which will control the braking pressure.Wheel rotating speed from the tachometer, aircraft speed data and braking pressure are supplied for A/Skid computation. The braking pressure is read on the triple indicator.The A/SKID regulation is disconnected, either electrically by setting the A/Skid & N/W Steering switch to the OFF position, BSCU failure or hydraulic low pressure (brakes being supplied by the brake accumulator only). The pilot must refer to the triple pressure indicator to limit brake pressure in order to avoid locking a wheel.With the accumulator pressure only, a maximum of 7 full brake pedal applications can be done. Nevertheless in that case the brake pressure is limited to max. 1000 PSI by the ABCU.PARKING BRAKEThe yellow hydraulic system or the brake accumulators supply brake pressure.Putting ON the parking brake, deactivates the other braking modes and the A/SKID system.