What happened
On September 6, 1964, during a flight day organized by the Motorfluggruppe Biel in Utzenstorf, a Piper Cub J3C (registration HB-OUD) was involved in a ground collision. After refueling at a station approximately 230 meters from the landing area, the pilot proceeded to taxi toward the takeoff position. Contrary to the established airfield organization, which required aircraft to taxi on the western side of the runway to avoid crossing the active area, the pilot remained on the eastern side. As the pilot maneuvered to align for takeoff, the aircraft's propeller and left landing gear struck the rear right section of a parked Opel automobile. The vehicle was owned by the airfield marshal.
The investigation
Investigators examined the movement of both the aircraft and the ground personnel during the event. It was established that the pilot's passenger had boarded the aircraft at the refueling point rather than at the designated western zone, prompting the pilot to stay east of the runway. The airfield marshal, positioned approximately 50 meters away at the northwest end of the runway, provided continuous flag signals instructing the pilot to continue taxiing. The investigation also determined that the marshal had parked his vehicle approximately 15 meters east of the landing T-marker, rather than on the nearby road as previously directed by the flight service manager.
Findings
Several contributing factors led to the collision:
- The pilot failed to adhere to the established airfield organization instructions regarding the taxi route.
- The pilot relied exclusively on the marshal's flag signals and failed to maintain adequate visual lookout for obstacles on the ground.
- The airfield marshal observed the aircraft approaching the vehicle but mistakenly assumed the pilot was performing an evasive maneuver, and therefore did not issue a stop signal.
- The marshal's decision to continue signaling the pilot to proceed, despite the deviation from the taxi plan, contributed to the incident.
- The vehicle was positioned in an area near the runway rather than on the designated roadway.