Flight History
On 19 June 2005, a two-seat L-13 "Blanik" glider operated by Vilnius Aeroclub departed Paluknis airfield at 13:20 local time for a training flight. The flight was part of a student's training program. Due to forecast thunderstorms with rain and winds up to 28 knots, the club's flight director decided that an experienced glider pilot would accompany the student as a "safety pilot" in the rear seat.
The flight proceeded to the training area southwest of the airfield, reaching about 10-12 km distance. As the planned flight time neared its end around 15:00, the pilots requested landing clearance. At that time, the glider was flying at an altitude of approximately 600 m over large meadows south of the airfield, about 3 km from the field.
While flying into the wind, the glider encountered a downdraft of 4-5 m/s. Descending to about 50 m altitude when roughly 1 km from the airfield, the pilots realized they would not be able to reach the runway. The rear-seat pilot took control, deciding to make a 180-degree left turn to land in the opposite direction, as landing straight ahead was considered too risky due to a village approximately 300 m ahead.
During the turn downwind, the glider stalled over a forest, struck tree tops, and fell into the woods.
Crew and Aircraft
The glider was occupied by a 17-year-old female student pilot and a 47-year-old male glider pilot. The student held a pilot-student license and had a total flight time of 29.26 hours, including 10.18 hours solo. The safety pilot held a valid glider pilot license (total 166.39 hours) but did not have instructor qualification.
The aircraft was an L-13 "Blanik" (registration LY-GAV) manufactured in 1979 by LET in Czechoslovakia. It had a valid airworthiness certificate, although the investigation noted that the certificate's expiry exceeded the calendar limit for the last major overhaul (due 2006-03-27, but certificate valid until 2006-06-08). The glider had accumulated 1666.56 total flight hours.
Weather
Weather conditions at the nearby Vilnius Airport (26 km southwest) at 14:50 reported wind 340° at 11 knots, visibility more than 10 km, 5-7 octas towering cumulus clouds with base at 4400 ft, temperature 22°C. A SIGMET warning for embedded thunderstorms was in effect for the area from 14:30 to 19:00. The forecast had indicated possible heavy rain and wind gusts up to 28 knots between 14:00 and 20:00.
Accident Sequence and Impact
The glider struck trees while in a stalled condition during the left turn. The impact left the glider irreparably broken. The left wing was torn from its attachment points, the right wing suffered structural damage, and the fuselage was broken. Despite the severe damage, both pilots were uninjured. They were wearing seat belts.
Probable Cause
The investigation concluded that the cause of the accident was the pilots' delayed decision to land in a selected field, the execution of a complex maneuver for the situation, and possible pilot error under stress, which led to an uncontrolled stall during the turn. The investigation also noted that the crew composition was inappropriate for the flight, as the safety pilot lacked instructor qualification and was not familiar with flying from the rear seat.