What happened
On 30 May 2015, a pilot was conducting a rehearsal formation flight at Blois-Le-Breuil aerodrome in preparation for an upcoming air show. The formation consisted of three aircraft: a Stampe SV4 (registration F-BAHL), another Stampe, and a Bücker Bü 131 Jungman.
After taking off and grouping, the formation descended to a height of 330 feet to perform a series of maneuvers. The lead pilot of the F-BAHL initiated a half-loop, at the top of which the wingmen departed the formation. As the pilot attempted a half-roll to finish the maneuver on his belly, the aircraft entered an uncontrolled left spin. The aircraft completed four rotations before impacting the ground. The pilot sustained fatal injuries, and the aircraft was destroyed.
The investigation
The investigation examined the aircraft's technical condition, the pilot's training, and the regulatory environment of the air show rehearsal. Technical analysis of the wreckage showed no pre-accident mechanical failures; the engine was producing power at the time of impact, and the flight controls remained functional.
Investigators also reviewed the pilot's credentials, noting he held a private pilot license and a first-level aerobatic rating, with training completed at a specialized center. The investigation noted that while the pilot had practiced formation flying, he had not specifically trained for the transition from formation flight to solo aerobatic maneuvers. Furthermore, the flight director's information regarding the display was found to be too brief to identify specific risks associated with the proposed maneuvers.
Findings
Several factors contributed to the accident:
- The primary cause was likely insufficient airspeed at the start of the aerobatic maneuver.
- The pilot may have experienced a false sensation of high speed due to the unusual proximity to the ground and the presence of a 60-degree left tailwind.
- A lack of specific training regarding the transition from formation flying to solo aerobatic maneuvers, particularly at low altitudes.
- The low altitude at which the maneuver began left the pilot with no opportunity to recover from the spin or deploy a reserve parachute.