What happened
On July 20, 2012, a private Dyn’aéro MCR Sportster, registration F-PSLX, was conducting a VFR flight from Cassagnes to Nangis. The pilot, flying solo, was operating above a layer of clouds and maintained contact with air traffic control until approximately 16:29. After inquiring about weather conditions at Châteauroux to determine if a descent was possible, the pilot ceased all radio communications. Radar contact was lost at 16:30.
Data from the pilot's portable GNSS receiver revealed that the aircraft initially flew a straight path, likely utilizing autopilot. The flight path then showed a period of climbing while groundspeed decreased to approximately 70 knots, indicating a possible stall condition. Subsequently, the aircraft entered a wide right-hand turn, during which the altitude dropped sharply to 8,300 feet and groundspeed increased to 172 knots, approaching the aircraft's maximum operating speed. Following this maneuver, the aircraft leveled off briefly before entering a steep, terminal dive toward the ground.
The investigation
Investigators examined the wreckage and debris field, noting that parts of the canopy were found 1,300 meters upstream from the main impact site, while the upper portion of the vertical stabilizer, attached to the elevator, was located 500 meters from the main wreckage. The wide distribution of cabin debris suggested a structural failure in flight.
Analysis of the flight path and debris indicated that during the extreme maneuvers, the canopy was likely damaged by the pilot's head or unsecured objects within the cabin. It is believed that these objects or fragments of the canopy struck the leading edge of the vertical stabilizer. This impact caused a loss of structural rigidity and subsequent vibrations that led to a progressive tear in the stabilizer, eventually causing the upper section and the elevator to separate from the airframe.
Meteorological analysis showed the aircraft was flying through an active area of convective clouds (cumulus congestus) with potential icing conditions above 9,000 feet. The pilot, a highly experienced flyer with over 730 total hours, did not hold an instrument rating.
Findings
- The primary cause was an insufficient assessment of meteorological conditions during flight preparation and execution.
- The pilot continued VFR flight in marginal to non-existent visibility conditions while flying above a cloud layer.
- An attempt to perform a turnaround maneuver led to a loss of control and extreme aerodynamic loads.
- The structural failure was triggered by internal cabin objects or canopy fragments striking the vertical stabilizer during these violent maneuvers, leading to the separation of the tail unit.