Factual Information
On 8 May 2012 at 09:25 UTC, a motor glider L-13 SW Vivat, registration OK-7104, operated by Aeroklub Kolín, was preparing for a cross-country flight at Kolín Airport (LKKO). The pilot, a 49-year-old holder of a valid glider pilot license with GLD and TMG ratings, had accumulated 470 hours on various types, including 60 hours on the L-13 SW.
The glider was unable to start moving under its own power because its main wheel was stuck in a depression on the airfield surface. A helper, who was assisting with the engine start, was asked by the pilot to push the glider. The helper pushed the glider by the left footstep, but the pilot did not fully reduce power, and the glider continued to taxi. As the helper ducked under the wing to clear the glider's path, he tripped and fell. The left elevator struck him in the back. The glider proceeded to the runway and took off.
During the takeoff roll, the pilot heard a bang, which he attributed to the tailwheel hitting a ground irregularity. He noted an unusual control force at the beginning but felt it normalized after trimming. After takeoff, he climbed to 300 m AGL. Shortly thereafter, the AFIS controller instructed him to return to the airport. The pilot executed a 180-degree turn and landed without further incident.
Damage and Findings
After landing, an inspection revealed damage to the elevator stabilizer hinge. The helper had observed asymmetrical movements of the elevator halves and reported this to the aerodrome flight information service (AFIS) controller, who then instructed the pilot to return.
The glider had a valid certificate of airworthiness and a total flight time of 1298 hours 40 minutes. Meteorological conditions were CAVOK with variable wind up to 4 knots.
Conclusions
The investigation determined that the pilot was fit for flight and the glider was airworthy. The helper contacted the aircraft while assisting the takeoff run. The pilot noticed a bang attributed to terrain, but no significant deviations. The helper reported abnormal elevator movements, leading to the return instruction. The elevator hinge was damaged. The glider was repaired and returned to service.
Probable Cause
The cause of the accident was the collision of the glider with the helper during its takeoff run.