What happened
On August 1, 2019, an Evektor Eurostar EV97 SL ultralight aircraft was conducting a sightseeing flight involving several intermediate stops. After departing from the Jesenwang landing field, the pilot visited Mengen and Aalen before beginning the return leg to Jesenwang.
During the final approach to runway 07, the pilot reduced engine power. Witnesses observed the aircraft enter a spinning motion and plummet toward the ground. The aircraft struck a cornfield approximately 1.5 km west of the airfield, where it was destroyed. The pilot sustained fatal injuries in the impact.
The investigation
The BFU examined the aircraft's wreckage, the engine, and the pilot's flight history. Radar data indicated the aircraft was descending from approximately 3,000 ft AGL and was last tracked at 1,800 ft AGL before the accident.
Investigators performed a detailed teardown of the Rotax 912 ULS engine. While the ignition, spark plugs, and gearbox showed no defects, the investigation focused on the carburetors. Testing revealed that the idle settings on both carburetors were incorrect, specifically that the float weight in one carburetor exceeded the maximum allowable limit. This caused the engine to drop to an idle speed of approximately 1,200 rpm during power reductions, which is below the manufacturer's minimum requirement of 1,400 rpm.
Findings
- The primary cause of the accident was the aircraft entering an uncontrolled flight attitude during final approach.
- A mechanical engine stall contributed to the accident, as the improper carburetor settings caused the engine to stop when power was reduced.
- The pilot's limited experience with this specific aircraft type and the sudden nature of the engine failure led to an inability to manage the resulting aerodynamic stall and spin at a low altitude.
- The pilot's total flight experience was relatively low, with only approximately 11 hours on the Eurostar EV97 SL.