What happened
On July 31, 2018, at approximately 07:45 UTC, a Wills Wing powered hang glider, registration OK-NZG 11, crashed into a tree near the villages of Vysoké and Lhotka. The pilot had prepared for flight at a temporary landing site on a field near the Velký les recreational area.
Shortly after takeoff from the southern edge of the field, the aircraft flew north and, approximately 400 meters from the departure point, struck a large tree located in an alley alongside a road. The impact caused the wing to become wedged in the tree, while the landing gear and engine assembly tore away from the airframe and struck the asphalt roadway. The pilot sustained multiple traumatic injuries and passed away during medical transport to the hospital.
The investigation
The ÚZPLN investigation examined the aircraft wreckage, the takeoff site, and witness testimonies. The investigation established that the aircraft's engine power had been reduced by approximately 20% due to unapproved technical modifications and the use of an unapproved propeller.
Investigators also reviewed the pilot's credentials and the aircraft's airworthiness status. It was determined that the pilot was flying with an expired pilot license and that the aircraft lacked a valid certificate of airworthiness and required third-party liability insurance. Furthermore, the takeoff was conducted from private land without the landowner's permission.
Findings
- The primary cause of the accident was the collision with an obstacle caused by an improper takeoff from the terrain.
- The pilot failed to perform an evasive maneuver to avoid the trees at the edge of the field and did not have sufficient altitude to clear them.
- The pilot underestimated the impact of environmental conditions, specifically the high ambient temperature and potential wind gusts, which affected engine performance and climb capability.
- The engine's performance was compromised by unapproved modifications to the powerplant.
- The pilot's protective helmet was not properly secured and fell off during the impact.
- The aircraft was not in a legal state for flight due to expired documentation and unapproved technical changes.