As He Released The Brakes To Begin Taxiing, The Brake Pedals Went To The Floor With No Braking Action Analysis: The pilot reported that during engine start up, he applied the brakes to the cargo airplane and remained stationary while he received a taxi clearance. As he released the brakes to begin taxiing, the brake pedals went to the floor with no braking action. He pumped the brakes several times with no effect, so he feathered both propellers and shut down the engines. The airplane continued to roll and collided with a parked airplane on the ramp.
