What happened
On the evening of March 5, 1968, at approximately 20:35 CET, a Piper Cub with registration HB-OAC was involved in a ground collision at the Locarno aerodrome. Following a night flight training session, the pilot attempted to taxi the aircraft back to its original parking position near the civil hangar. During this maneuvering, the pilot failed to observe a Cessna 150, registration HB-CBY, which had been parked in the intended spot during the intervening period.
As the pilot approached the parking area, the engine power was reduced, which coincided with a significant dimming of the aircraft's onboard headlight. Consequently, the HB-OAC struck the tail section of the stationary HB-CBY with its metal propeller, causing minor damage to the latter.
The investigation
The investigation established that the HB-OAC was airworthy and held valid registration under its owner, Fa Aviation Market SA. The pilot held a valid private pilot license with approximately 146 flight hours.
At the time of the incident, the hangar doors were open, and floodlights were active, illuminating the apron area up to approximately 20 meters. The investigation examined the lighting conditions and noted that the HB-CBY was not displaying any position lights. Investigators also considered whether a voltage drop in the electrical system, caused by the reduction in engine power, contributed to the dimming of the taxi light.
Findings
- The primary cause of the accident was that the pilot failed to sufficiently account for the limited visibility conditions while taxiing.
- The pilot did not anticipate that the previously vacant parking space would be occupied by another aircraft.
- A reduction in engine power may have led to a drop in electrical voltage, significantly reducing the effectiveness of the onboard headlight.
- The stationary aircraft was positioned between the taxiing aircraft and the illuminated hangar area, making it potentially detectable with increased vigilance.