What happened
On June 15, 1964, a Jodel U2-MFGZ was conducting a VFR flight from Kloten to Prangins. During the flight, while flying over the region of Proideville, the pilot experienced a sudden drop in engine RPM. The pilot realized the right fuel tank had run dry and attempted to switch to the left tank, which still contained approximately 25 liters of fuel.
Despite attempts to restore power, the engine continued to struggle. While attempting to contact Lausanne Tower for landing instructions, the pilot navigated toward the Blécherette airfield. Realizing they could not reach the runway due to terrain and a line of trees, the pilot opted to land in a field west of the aerodrome. During the final approach, the aircraft encountered an 8-meter high power line. In an attempt to clear the obstacle, the pilot pulled back on the control column, causing the aircraft to lose speed and stall. The aircraft struck the ground heavily on its main landing gear, causing it to nose over and capsize.
The investigation
The investigation examined the fuel system, the engine, and the pilot's actions. Investigators found that the fuel system was intact and the fuel itself was uncontaminated. While the fuel selector valve was noted to be difficult to operate, tests confirmed it provided sufficient flow.
Crucially, the investigator analyzed the pilot's recent flight history and noted that the pilot had recently flown a Jodel DR 1050, which features a different fuel selector configuration where tank positions are diametrically opposed. The investigation also included flight tests to determine how long it took for the engine to recover during fuel switching.
Findings
- The primary cause of the engine failure was a pilot error involving the fuel selector valve. It is highly probable that while attempting to switch from the empty right tank to the left tank, the pilot instinctively rotated the valve 180 degrees instead of the required 90 degrees, inadvertently moving it to the "closed" position.
- The pilot's decision to attempt to fly over the power line rather than under it led to a loss of airspeed and the subsequent heavy landing and capsize.
- The pilot spent valuable time attempting to establish radio contact with Lausanne Tower, which was not strictly necessary given the emergency situation.
Safety action
No specific safety recommendations were recorded in this report.