What happened
On June 30, 2007, at 14:45 UTC, an L 13A Blanik glider, registration OK-2cap, was involved in a fatal accident approximately 2 km east of the Frýdlant nad Ostravicí airport (LKFR). The flight, a training session involving an instructor and a student, had been launched via aero-tow by a Z 42 aircraft.
After approximately one hour of soaring near Lysá hora, the instructor observed a decline in thermal convection. At an altitude of 1,300 meters, the instructor decided to return to the aerodrome. However, unexpected strong sinking air behind the northern ridge of Lysá hora prevented the glider from crossing the ridge. To avoid the terrain, the instructor attempted to fly around the northern end of the ridge.
During this maneuver, the glider flew at an insufficient altitude over forested terrain. Witnesses reported that the aircraft first struck the treetops, which caused it to lose airspeed. Following the initial contact with the trees, the glider entered a left-hand spin. During the spin, the aircraft struck the ground nose-first. The accident resulted in one fatality (the student) and one serious injury (the instructor). The aircraft was destroyed upon impact.
The investigation
The ÚZPLN investigation examined the flight sequence, the meteorological conditions, and the pilot's decision-making process. The investigation confirmed that the instructor held valid glider pilot, glider instructor, and medical certifications. The aircraft, OK-2724, was also found to be airworthy, having undergone its annual inspection only ten days prior to the accident. Meteorological data showed CAVOK conditions with a light wind, indicating that weather conditions were suitable for a safe landing in the terrain.
Findings
- The instructor misjudged the development of thermal convection and failed to decide on a return to the aerodrome in a timely manner.
- While attempting to bypass the northern ridge, the pilot failed to adhere to minimum altitude regulations regarding flight over forested areas.
- A safe landing in suitable terrain was possible in the area where the pilot attempted to fly around the ridge.
- The primary cause of the accident was the instructor's decision to continue the flight to the home aerodrome instead of performing a safe landing in available terrain.