What happened
On July 21, 1965, a Bü-131 Jungmann A-57 was operating near the Yverdon aerodrome when the aircraft experienced a sudden loss of power. During the flight, the pilot inadvertently closed the fuel cock, cutting off the fuel supply to the engine. Unable to maintain flight with the fuel supply interrupted, the pilot was forced to perform an emergency landing in a nearby field.
The investigation
The investigation focused on the sequence of actions leading to the engine failure. It was established that the pilot had mistakenly moved the fuel valve from the required cruise flight position to the closed position while still in the air. The aircraft sustained substantial damage, estimated at 75 percent of its value, due to the impact of the emergency landing.
Findings
- The primary cause of the engine failure was the accidental closure of the fuel valve during flight.
- The pilot failed to ensure the fuel cock remained in the proper "cruise flight" position.
- The pilot emerged from the incident without any injuries.