The day before an air show at Blois aerodrome, three pilots performed a formation flight for the flight director’s validation. The F-BAHL pilot was the lead pilot of the formation consisting of two Stampes and one Bücker Bü 131 Jungman.
Shortly after the three aircraft had simultaneously started their ascent, the wingmen simultaneously left the lead pilot, who first performed a half loop. At the top of this loop, the aircraft entered a half-rollin an anti-clockwise direction in order to finish on its belly, continue its ascent and start a series of solo aerobatic figures.
As it rolled over onto its belly, the aircraft entered an uncontrolled left spin, and made four complete turns before colliding with the ground, its wings practically level and with a nose-down attitude of around 30°.
The entry into the uncontrolled spin at the end of the split-S is probably the result of too low a speed at the start of the figure.
The low height at the beginning of the aerobatic maneuver, and thus the low height at which the spin started, did not allow the pilot time to recover from the spin or attempt to eject.