Background
On 18 June 2016, at approximately 09:15 UTC, a L-23 Super Blaník glider, registration OK-5525, operated by Aeroklub Kyjov, was involved in an accident at Kyjov Airport (LKKY). The glider was occupied by two pilots: Pilot A (age 63) and Pilot B (age 66). Both held valid glider pilot licenses and medical certificates.
Flight History
Pilot A, seated in the front seat, initiated a takeoff via aerotow at about 09:00 UTC, seeking thermal lift. After releasing from the tow aircraft approximately five minutes later, he was unable to find sufficient lift to remain airborne and decided to return to the departure airport. He entered a left-hand circuit for Runway 33 downwind at an altitude of about 250 meters above ground.
During the approach, the pilots observed several other gliders positioned on the left side of the runway. They opted to land on the right side, designated for motorized aircraft. At this point, Pilot A requested Pilot B to take control and perform the landing.
Pilot B assumed control at an indicated airspeed of 80–90 km/h and proceeded into the fourth turn, performed at an altitude of 200–220 meters above ground. He reported final approach via radio. Initially, he partially extended the airbrakes, but upon encountering a relatively strong downdraft (4–5 m/s), he immediately retracted them and did not use them again. The glider descended through the downdraft, and at about 20 meters above a rapeseed field, the airspeed was 90 km/h. Pilot B was confident of a safe landing on the airport. However, the glider settled over the rapeseed at approximately 70 km/h, and its tail surfaces caught the crop, causing the glider to decelerate and strike its front section against an elevated bank bordering the airfield. The glider bounced and came to rest on the airport surface, rotated about 90 degrees left.
Damage
The impact caused wavy skin on the fuselage and center section, and damage to the main and tail landing gear attachments. The glider required manufacturer repair before further flight.
Investigation Findings
The investigation determined that both pilots were fit for flight, the glider had a valid airworthiness certificate, and weather conditions were suitable. During the descent after the fourth turn, Pilot B was confident in his landing judgment. The glider's speed during the approach fell below the minimum approach speeds specified in the flight manual for the L-23 Super Blaník. The pilot did not effectively respond to the glider's settling at a speed lower than recommended.
Probable Cause
The cause of the accident was the glider's impact with the ground during approach to landing. The impact occurred before the airport after the glider settled at an approach speed lower than specified in the flight manual for the L-23 Super Blaník.