Parking Brake

Parking Brake schematic Left Hydraulic system Right Hydraulic system Brake Accumulator Autobrakes Control system

The parking brake can be set with the normal/reserve or alternate brake hydraulic system. If the normal/reserve and alternate brake systems are not pressurized, parking brake pressure is maintained by the brake accumulator. The brake accumulator is pressurized by the right hydraulic system. Accumulator pressure is shown on the BRAKE PRESS indicator.

The parking brake is set by depressing both brake pedals fully, while simultaneously pulling the parking brake handle up and then releasing the brake pedals. This mechanically latches the pedals in the depressed position, the brake metering valves open and commands the parking brake valve in the antiskid return line to close which prevents the antiskid system from bleeding off brake pressure.

The parking brake is released by depressing the pedals until the parking brake handle releases.

The PARK BRAKE light illuminates and the EICAS advisory message PARKING BRAKE displays when the parking brake is set (parking brake valve not open).

Brake Pressure Indicator

Brake Pressure Indicator

The Brake Pressure Indicator shows the pressure in the Brake Accumulator. An initial pre-charge is shown by the amber band (1300 psi) on the indicator. A reading at or below the amber band indicates no Brake Accumulator pressure is available.

Brake Units