What happened
On the evening of September 13, 1959, a collision occurred at the Lachen-Wangen airfield involving two Piper J3 and C (L4) aircraft, registrations HB-OIR and HB-OBP. The incident took place at approximately 18:10 local time during a period of clear skies and low wind.
The pilot of HB-OIR was performing a standard landing approach on the grass runway. Simultaneously, the pilot of HB-OBP, who was acting as the airfield duty manager that afternoon, was taxiing toward the runway after refueling at a nearby pump. While the landing aircraft was hovering approximately half a meter above the ground, it struck the taxiing aircraft, which was crossing the runway at an angle.
The impact caused significant damage to both aircraft. The rear fuselage and tail of HB-OBP were destroyed, while the engine, propeller, and landing gear of HB-OIR sustained heavy damage. Despite the severity of the impact, there were no injuries to the pilots or passengers involved in either aircraft.
The investigation
The investigation examined the flight paths, airfield regulations, and environmental conditions. Investigators noted that the sun was positioned low on the horizon, directly aligned with the runway axis, which could have caused glare for the pilots.
Regarding the taxiing aircraft, the investigation found that the pilot of HB-OBP failed to follow the established taxiway procedures. Instead of taxiing along the southern edge of the runway to the designated takeoff point, the pilot crossed the runway approximately 100 meters from the western end. Furthermore, the pilot was distracted by a loose window screw that had fallen onto the cabin floor, which he attempted to retrieve without stopping or slowing the aircraft.
Findings
- The primary cause of the collision was the failure to adhere to taxiway regulations by the pilot of HB-OBP.
- The pilot of HB-OBP failed to maintain adequate airspace surveillance, a responsibility heightened by the fact that landing aircraft have the right of way.
- The pilot of HB-OBP continued taxiing at an unreduced speed while distracted by an internal cabin issue.
- The pilot of HB-OIR was unable to avoid the collision because the crossing aircraft appeared immediately in front of the landing aircraft's flight path, leaving no time for evasive maneuvers.