What happened
On the morning of August 7, 1975, a Beech Bonanza B35, registration HB-EGA, departed from Yverdon airfield for a flight to Cannes, with a planned stop in Geneva. The aircraft was carrying the pilot and two passengers. Shortly after takeoff from runway 25, the engine began to sputter. As the aircraft climbed to an altitude between 50 and 200 meters, the engine experienced intermittent failures before stopping completely.
Following the engine failure, the aircraft entered a right-hand turn and then veered left toward the Jura mountains. While attempting an emergency landing, the aircraft flew through a line of trees and entered a stall. The plane struck a cornfield in Suscévaz, approximately one kilometer from the end of the runway. The impact destroyed the aircraft. The pilot was killed, and the two passengers sustained serious injuries.
The investigation
Investigators examined the fuel system and the wreckage to determine the cause of the engine failure. The aircraft was equipped with two wing tanks and one auxiliary tank. Analysis of the wreckage and subsequent fuel sampling revealed that the left wing tank contained less than the minimum usable fuel. While the right wing tank and the auxiliary tank held sufficient fuel, the fuel selector was found in the left tank position.
Technical examination of the engine and fuel lines showed no signs of mechanical failure or leaks. The fuel pump was found to be in perfect working order. The investigation also noted that the pilot had prepared for the flight alone, and while he believed he had enough fuel to reach Geneva, the actual distribution of fuel across the tanks was critically low in the left wing.