What happened
On 12 February 2017, a Piper PA19 Super Cub, registration F-BOUF, was conducting an instructional flight at Chavenay-Villepreux aerodrome. The flight involved a student pilot and an instructor performing low-altitude aerodrome circuits to practice maneuvers. After completing two initial circuits at heights of 150 ft, the crew began a third left-hand circuit at an altitude of approximately 100 ft.
As the aircraft initiated the turn at the end of the downwind leg, it entered a stall. The aircraft subsequently struck the aerodrome perimeter fence before impacting the ground near the threshold of runway 10. The aircraft sustained substantial damage, though no injuries were reported.
The investigation
The BEA investigation examined the flight profiles, pilot experience, and aircraft configuration. The investigation established that the aircraft was operating at a weight of 693 kg, which exceeded its maximum allowable takeoff weight of 681 kg. The aircraft was not equipped with a stall warning system, and only the pilot in the front seat had access to the flight instruments.
Investigators also reviewed the regulatory environment regarding low-height circuits. At the time of the accident, regulations allowed for training-specific circuits at heights different from the standard 1,000 ft pattern, but the specific minimum height for these maneuvers was not defined in the aerodrome's charts.
Findings
Several factors contributed to the accident:
- The crew elected to perform circuits at extremely low altitudes (between 100 and 150 ft) without a specific educational objective.
- A stall occurred during the turn at the end of the downwind leg, from which the crew could not recover before impact.
- A sense of emulation between the instructor and the student pilot may have impaired their judgment regarding the risks of the low-altitude maneuvers.
- A lack of regulatory limitations regarding the minimum altitude for low-height circuits at that time allowed the maneuver to be performed at an unsafe height.