What happened
On May 24, 1971, a pilot departed from Basel-Mulhouse Airport for a local flight in a Smaragd CP-301 S, registration D-ELHI. Approximately ten minutes into the flight, the aircraft was observed performing low-altitude maneuvers, including loops and rolls, near Therwil and Hofstoden. During a climbing maneuver, the aircraft lost airspeed and entered a steep spin. Although the pilot managed to recover from the spin after several rotations, the aircraft was at an insufficient altitude to recover before impacting the ground near the Mariastein-Hofstetten road. The impact resulted in the death of the pilot and the total destruction of the aircraft.
The investigation
The investigation, conducted alongside the Solothurn Cantonal Police, examined the pilot's credentials, the aircraft's mechanical state, and the environmental conditions. Investigators found that the pilot's flying license had been revoked by German authorities shortly before the accident. Furthermore, post-mortem analysis by the University of Bern revealed a blood alcohol content of approximately 1.0‰ and evidence of chronic alcoholism. The aircraft's controls were found to be properly connected and secured, and there was no evidence of mechanical failure. The investigation also noted that the pilot was not wearing a parachute.
Findings
- The pilot was flying without a valid pilot certificate, as his license had been revoked on May 11, 1971.
- The pilot was under the influence of alcohol at the time of the accident.
- The pilot lacked specific training in aerobatic maneuvers.
- The pilot failed to recover from a spin in a timely manner due to the low altitude maintained during the maneuvers.