What happened
On August 15, 2000, at approximately 08:38 UTC, a Flight Design CT ultralight aircraft departed from runway 28 at Seitenstetten Airfield (LOLT) for a local circuit flight. The aircraft had previously arrived from St. Georgen (LOLG) and had refueled with 60 liters of fuel prior to departure.
During the initial climb, at an altitude of approximately 30 meters above the ground, the engine began to sputter and subsequently failed. The pilot attempted to restart the engine, but the attempt was unsuccessful. The pilot performed an emergency landing in a harvested field located to the right of the runway safety strip, heading north. Upon touchdown, the aircraft underwent a rollover. The pilot sustained no injuries, though the aircraft suffered extensive damage to the nose gear, vertical stabilizer, engine cowling, propeller, right main landing gear, and the left wing, which split approximately one meter.
The investigation
The investigation examined the fuel system and engine components to determine the cause of the power loss. Investigators analyzed the fuel levels in both tanks, noting approximately 40 liters in the left tank and 20 liters in the right tank. An inspection of the ignition system showed that the spark plugs were in good condition. However, examination of the fuel filtration system revealed the presence of dirt particles in the coarse fuel filter. Furthermore, the fine fuel filter exhibited a foamy consistency immediately following the accident. The investigation also identified irregularities in the fuel return system, noting that the intended return to the right tank was not functional because the connection had been disconnected. Instead, the return flow had been routed via an uninsulated plastic line positioned near the exhaust manifolds to reach the coarse filter.