What happened
On October 27, 2007, a North American T-6G, registration HB-RDC, was participating in a flight day organized by the Club Neuchâtelois d'aviation at Neuchâtel Airport (LSGN). During the second flight of the day, the aircraft departed from runway 05. Shortly after takeoff, while at an estimated altitude of 50 meters, the engine experienced significant power fluctuations and loud detonations.
Following a reduction in power, the aircraft began to deviate from its flight path, banking sharply to the left and then to the right. The engine eventually ceased functioning entirely. The aircraft subsequently entered a stall and crashed into a wooded area near a residential zone, approximately 400 meters beyond the end of the runway. The impact caused a localized fire, which was suppressed by neighbors and firefighters. The pilot was killed upon impact, and the passenger sustained critical injuries that led to death later that same day. The aircraft was destroyed.
The investigation
The investigation examined the aircraft's technical systems, the pilot's experience, and audio recordings from a nearby spectator's video. Investigators performed ground tests on a similar T-6G model to replicate the engine's acoustic signature. These tests confirmed that moving the mixture control to a specific position produced the same engine detonations heard during the accident.
Technical inspections of the fuel system and engine components revealed no mechanical failures or defects that would have caused a spontaneous loss of power. The investigation also noted that the pilot, while highly experienced in single-engine aircraft, had less than 15 total flight hours on this specific type, with much of that experience gained in the rear seat as an instructor.
Findings
- The engine failure was likely caused by the unintentional movement of the mixture control during the pilot's attempt to reduce power using the manifold pressure and propeller levers.
- The loss of power occurred at a very low altitude and low airspeed, leaving the pilot with only a few seconds to react.
- The pilot's attempts to maneuver the aircraft to survey the terrain likely contributed to a loss of control and a subsequent stall.
- The aircraft was within weight and center of gravity limits, and the weather conditions were not a contributing factor.