Preflight and Engine Start
At dawn, a pilot and a mechanic conducted a preflight inspection of the aircraft before a local maintenance test flight. The aircraft's engines were started with the hydraulic system circuit breaker not engaged.
Loss of Brake Pressure
As the right engine's RPM increased, the aircraft began to move forward. The pilot attempted to apply the brakes but discovered that there was no hydraulic pressure in the brake lines.
Collision
Before corrective action could be taken, the aircraft struck a parked aircraft.
Cause
The hydraulic system circuit breaker was not engaged when the engines were started, rendering the brakes inoperative.