Incident Overview
Two pilots and a mechanic were conducting a post-maintenance test flight to check the ailerons after control system work. Prior to the flight, the aircraft's maintenance records indicated that the right brake master cylinder had been replaced. Additionally, the original PT6-112 engines had been swapped for new PT6-135 engines fitted with new four-bladed propellers.
Pre-Flight and Engine Start
The company that installed the engines and propellers stated that these components had not been rigged after installation because the aircraft was scheduled to go to the paint shop; the rigging remained an open item at the time of the accident. The pilot reported that before starting the engine, he tested and held the brakes. After engine start, the right brake pedal slowly traveled to the floor, and the aircraft began moving forward while turning left. Attempts to pump the right pedal to restore brake pressure were unsuccessful.
Evasive Maneuver and Collision
A loaded Cessna Citation was parked directly ahead. To avoid it, the pilot intentionally kept the aircraft turning left while moving the throttle levers into reverse to stop. When the aircraft failed to stop, he pulled the propeller levers to feather and the condition levers to stop. During this process, the aircraft continued moving, and the left wing struck a parked Cessna 425.
Post-Incident Examination
FAA airworthiness inspectors examined the aircraft and found that the engine and propeller rigging was out of specification to the extent that the propeller blades could not move beyond a zero blade angle. Taxi tests conducted after the incident revealed no anomaly with the brake system. The engines and propellers, as rigged, would not provide any braking or reverse thrust. A detailed inspection found no evidence of brake fluid leakage. The right brake master cylinder was removed from the aircraft and tested; it performed to factory specifications for a new cylinder.
Probable Cause
The investigation did not state a probable cause.