What happened
On October 21, 2008, an Allegro 2000 ultralight aircraft, registration OK-KUA 20, crashed near the village of Hluboké Dvory in the Czech Republic. The flight originated from Bohuňovice airfield, with the pilot intending to land at a landing area near Lysice.
Data recovered from a handheld GPS device revealed that after takeoff, the pilot performed several maneuvers, including changes in direction and altitude. As the aircraft progressed toward the south and west, it encountered deteriorating weather. The flight path eventually led the aircraft into rising terrain, which reduced the aircraft's altitude above the ground. In the final minute of flight, the pilot executed four separate climbs and descents at very low altitudes. The final climb ended at a speed of 56 km/h and an altitude of approximately 444 m AMSL. This was followed by a rapid descent and a sudden change in direction, resulting in a high-energy impact with the terrain. Both the pilot and the passenger sustained fatal injuries.
The investigation
The ÚZPLN investigation reconstructed the flight path using data from a Garmin eTrex Vista GPS unit found at the scene. The investigation also reviewed witness statements and examined the aircraft's technical condition.
Investigators found that the aircraft was overweight by 24.75 kg at the time of the accident. The engine was found to have been operating normally until the impact. Meteorological analysis confirmed that while conditions were suitable at takeoff, the aircraft encountered low cloud layers and reduced visibility, which were unsuitable for Visual Flight Rules (VFR) operations.
Findings
- The primary cause of the accident was the aircraft entering weather conditions that did not permit VFR flight.
- The aircraft entered a right-hand spiral due to a loss of airspeed at a low altitude, which the pilot could not recover from due to the limited height above the ground.
- The pilot's attention was likely diverted from aircraft control due to the progressive loss of visual contact with the terrain.
- The aircraft was operating above its maximum takeoff weight.
- The use of a handheld tourist GPS for navigation was noted as an inappropriate choice for aviation use due to poor ergonomics and lack of aeronautical data.