Aircraft and Pilot Information
The aircraft involved was a Piper Cub registered as HB-OAC, owned and operated by Aviation Market SA, Bern. It held a valid airworthiness certificate with no indications of pre-existing mechanical issues. The pilot possessed a valid private pilot license and had accumulated approximately 146 flight hours.
Circumstances of the Accident
On the evening of 5 March 1968, at approximately 2035 MEZ, the pilot had just completed a night flight training session at Locarno airfield. Alone on board, he taxied the Piper Cub back to the parking area near the civil hangar, intending to park it in the same spot where he had boarded about an hour and a half earlier. The hangar door was open, and exterior lamps illuminated the apron for about 20 meters. To see ahead, the pilot used the aircraft's landing light, which was aimed steeply downward, limiting its forward illumination.
As he approached the intended parking position, he reduced engine power. According to the pilot's account, the landing light then became very dim, possibly due to a voltage drop in the electrical system. Unaware that another aircraft—a Cessna 150 registered as HB-CBY—had been parked in that spot during his absence, he taxied into it. The Piper Cub's metal propeller struck and damaged the empennage of the Cessna. The Cessna was not equipped with position lights.
Location and Visibility Conditions
The collision occurred approximately 40 meters in front of the civil hangar. At the time, the hangar doors were open and two large angled lamps in the gable end illuminated the apron for about 20 meters. Weather conditions had no influence on the accident. The pilot's visibility was compromised by the dimmed landing light and the fact that the Cessna was positioned between the Piper Cub and the lit hangar apron, making it less conspicuous.
Discussion
The investigation considered that the power reduction likely caused a voltage drop, significantly reducing the landing light's intensity. Nevertheless, the parked Cessna might have been spotted with ordinary attention, despite the somewhat unfavorable visibility from the Piper Cub's cockpit. The pilot apparently did not anticipate that the space his aircraft had occupied before the flight would be taken by another aircraft during the interim.
Conclusion
The accident is attributed to the pilot not sufficiently accounting for the restricted visibility conditions.