What happened
On November 19, 2013, a SOCATA TBM700B, registration N115KC, departed Annecy Meythet for Toussus-le-Noble under IFR conditions. The aircraft was carrying the pilot and five passengers. While cruising at FL180 near Auxerre, the pilot requested and received clearance to descend to FL120.
During the descent, the aircraft's trajectory deviated to the left. Air traffic control queried the deviation, to which the pilot responded that they were correcting the course toward the EBOMA waypoint. Shortly after, the aircraft's path curved to the right while continuing its descent. At 11:16, the controller notified the pilot that the aircraft had descended below FL120, but no response was received. Radar data indicated a rapid increase in vertical speed, exceeding 10,000 ft/min, followed by the loss of radar contact. The wreckage was located in a field approximately 800 meters from the last radar contact point.
The investigation
The investigation examined the wreckage, radar data, radio communications, and meteorological conditions. The aircraft struck the ground in a steep nose-down attitude with high energy, leaving no evidence of a bounce or slide. While the extent of the damage prevented a full examination of the flight controls and cockpit, investigators noted that the landing gear and flaps were retracted, the engine and propeller were rotating upon impact, and the trim controls were near neutral.
Radio analysis showed the pilot's voice was calm and no alarms were heard during the final communications. Meteorological data indicated the presence of clouds and fog in the area, with some models suggesting potential moderate icing at FL130, though the aircraft's stable cruise speed suggested no significant icing had occurred prior to the descent.
Findings
- The aircraft entered a steep nose-down dive following a period of lateral deviation during descent.
- The pilot had very limited experience on the TBM700 type, having completed only a few hours of specific training just days before the accident.
- The lack of visual references due to low visibility and cloud cover likely increased the pilot's workload.
- The investigation could not definitively determine the cause of the loss of control due to the lack of flight recorders and the severity of the impact, though it could not be ruled out that an unusual situation or failure occurred.
- The absence of flight recorders on this class of aircraft prevented the establishment of the exact circumstances leading to the loss of control.