What happened
On September 24, 1980, a Piper PA-28-180, registration HB-OVY, was involved in an accident near Belp, Switzerland. The pilot had previously drained the left fuel tank and part of the right tank to maximize tax-free fuel collection for a planned flight to Germany the following day. Although no flight was scheduled for the 24th, the pilot decided to conduct a VFR flight from Bern to Gruyères and back with three passengers.
During the return leg via Murten, the pilot noticed the right fuel gauge had reached empty near the Gurten area. As the aircraft passed Kehrsatz, the engine failed. The pilot attempted to switch to the left tank, but the engine only ran for a few seconds before stopping completely. While attempting an emergency landing on a grass field, the aircraft struck a high-voltage power line at low altitude. The impact caused the aircraft to strike the ground with a heavy nose-down attitude, resulting in the destruction of the plane. The pilot and one passenger sustained serious injuries, while the other two occupants suffered minor injuries.
The investigation
The investigation established that the left fuel tank was completely empty at takeoff, and the right tank contained only approximately 20 liters of fuel plus remaining residue. While the pilot had reported a fuel endurance of one hour on the flight plan, the actual fuel remaining at takeoff was only about 48 minutes. Investigators found that the pilot was aware the left tank was empty due to the prior draining process. Furthermore, the investigation determined that the pilot failed to execute the shortest possible route to a runway once the fuel depletion became apparent.