What happened
On April 4, 2016, at approximately 10:10 local time, a RagWing Special ultralight aircraft, registration OK-BUL03, crashed near the Ústí nad Labem airport (LKUL) in the Czech Republic. The aircraft was being operated by a private individual for the purpose of testing ground taxiing maneuvers.
Witnesses observed the aircraft flying at a very low altitude, no more than 50 meters, performing two 360-degree left turns near the northeast edge of the airfield. The aircraft then departed toward runway 23. A few minutes later, the aircraft was seen returning toward runway 05, flying extremely low—passing just above 9-meter high low-voltage power lines. Witnesses noted the aircraft was flying very slowly, describing the engine sound as being similar to a scooter. After completing a right turn into a westward heading, the aircraft began to fall flatly toward the ground. The aircraft struck the western slope of a liquid waste storage tank in a nearby collection yard, causing heavy damage to the airframe and the death of the pilot.
The investigation
The ÚZPLN investigation examined the aircraft's condition, the pilot's qualifications, and the flight sequence using witness statements and airport camera footage. The investigation revealed that the aircraft was an amateur-built replica of a Pitts Special. At the time of the accident, the aircraft did not have a valid technical certificate or required insurance. The pilot had recently performed work to reinstall a new engine and instrument panel to re-register the aircraft.
Technical examination of the wreckage showed significant damage to the right lower wing and the landing gear, which had been forced into the fuselage. Investigators performed a test run of the engine in a hangar. While the engine was found to be mechanically functional, the investigation confirmed that the fuel system was empty at the time of the crash. Only 100 ml of fuel was recovered from the fuel lines during the inspection.
Findings
- The primary cause of the accident was the complete exhaustion of fuel during flight at a low altitude and low airspeed.
- The pilot had no realistic opportunity to recover from the situation once the engine failed at such a low altitude.
- The propeller damage indicated that the engine was not producing power at the moment of impact.
- The aircraft was not officially registered in the LAA ČR central registry and lacked a valid technical certificate.
- The pilot was likely not wearing a seatbelt at the time of impact, based on the nature of the injuries, though this could not be definitively proven.
- Weather conditions were clear (VMC) and did not contribute to the accident.