What happened
On 23 May 2021, a CAP 10BK aircraft, registration F-GGYC, was performing aerobatic maneuvers over the Durance river near Peyrolles-en-Provence. The pilot, accompanied by a passenger, had departed from Aix-Les Milles aerodrome shortly before 19:30.
Digital accelerometer data and radar tracking indicate that the pilot executed a sequence of maneuvers, including loops, rolls, and a hammerhead. Following a period of inverted flight, the aircraft entered a high-energy descent. The final recorded maneuver was likely an "English bunt," characterized by a steep nose-down attitude. During this phase, the aircraft's vertical G-forces dropped to as low as -3.9 g. The aircraft subsequently struck the surface of the Plan d’eau des Chapeliers lake at high speed. The impact resulted in the destruction of the aircraft and the fatal injuries of both the pilot and the passenger.
The investigation
The BEA examined the wreckage, which was recovered from 15 meters below the water. While the aircraft was heavily fragmented, investigators analyzed the engine and control linkages. The engine showed no signs of mechanical failure, though the fuel injection system was found to be adjusted with an abnormally lean mixture. Control linkages appeared continuous, though a technical failure could not be entirely ruled out due to the extent of the damage.
Investigators also analyzed the pilot's medical history and the physiological effects of the maneuvers. The pilot was taking prescribed medication for high blood pressure, including a diuretic and an angiotensin II inhibitor. The investigation focused on the "push-pull effect," where the transition from negative G-forces (inverted flight) to positive G-forces can significantly reduce a pilot's tolerance to acceleration.
Findings
- The aircraft entered a steep, uncontrolled descent following a sequence of maneuvers involving both positive and negative G-forces.
- The pilot's use of antihypertensor medication may have reduced his physiological tolerance to rapid changes in G-load.
- The transition from negative to positive G-forces (the push-pull effect) likely contributed to a state of G-induced loss of consciousness (G-LOC) or almost loss of consciousness (A-LOC), or potentially spatial disorientation.
- The high-energy impact with the water was the direct cause of the aircraft's destruction and the fatalities.