What happened
Following recent maintenance work involving the installation of a new right-side engine and the re-rigging of both propeller assemblies, the pilot initiated a test flight. While ground operations and initial checklists were completed without significant issues, a discrepancy was noted where the right engine propeller idled at a higher RPM than the left.
During the flight, the aircraft successfully completed its takeoff roll and initial climb. However, upon reaching an altitude of approximately 100 feet, the aircraft ceased to climb and experienced a significant loss of airspeed. Unable to rectify the issue, the pilot executed a forced landing into uneven, hilly terrain. The impact caused the landing gear to collapse and damaged the engine nacelles, which led to an aircraft fire.
Findings
An investigation into the accident determined that the propeller beta valves on both engines had been incorrectly rigged. This improper configuration caused both propellers to enter the feather position immediately after the takeoff sequence activated the landing gear squat switch. It was also noted that the maintenance staff lacked the specific rigging expertise required for this particular aircraft type. Following the incident, the manufacturer issued clarifications regarding the procedures found in the pilot handbook and maintenance manuals.