Brake mechanism for air turbine starter

A brake assembly (44) for an air turbine starter (10) includes a brake cylinder (46). A brake piston (48) is located at least partially within the brake cylinder (46) and slidable therein. A biasing member (50) biases the brake piston (48) toward a turbine wheel (12) of the air turbine starter (10) applying a braking force to the turbine wheel (12) and defining a piston chamber (58) between the turbine wheel (12) and the brake piston (48). A through opening (56) in the brake piston (48) into the piston chamber (58) is configured such that a flow of fluid through the through opening (56) into the piston chamber (58) applies a force to the brake piston (48) sufficient to overcome the bias thereby allowing rotation of the turbine wheel (12).