Accident Overview
On 18 May 2019 at 12:50 UTC, a Standard Cirrus glider, registered OK-5847, was involved in an accident during an aerotow takeoff from runway 06 at Chrudim Airport (LKCR). The glider was being towed by a Z 226 MS aircraft. During the initial ground roll, the glider veered to the right due to crosswind, the towline attachment at the center of gravity, and limited rudder effectiveness at low speed. As speed increased, the glider began to align with the towplane and became airborne. However, after release, the right wing likely contacted tall grass at the edge of the runway, causing the glider to yaw sharply to the right. The pilot released the tow rope, and the glider struck the ground with a 90° deviation from the takeoff direction, coming to rest approximately 15 meters to the right of runway 06.
Pilot Information
The glider pilot, aged 33, held a valid glider pilot license and a valid medical certificate (Class 2). He had accumulated 297 hours total on gliders, with 139 hours on the Standard Cirrus type. In the previous 90 days, he had flown 4 flights totaling 1 hour 43 minutes, including one previous aerotow takeoff in the same glider type.
The tow pilot, also 33, held a valid Private Pilot License (A) with SEP land and towing (TOWING-S) ratings. His total flight time was 222 hours 59 minutes, including 49 hours 54 minutes on the Z 226 MS and 16 hours 8 minutes as a tow pilot.
Aircraft and Damage
The Standard Cirrus is a single-seat, mid-wing glider with a composite fuselage and T-tail. The glider (OK-5847) was manufactured in 1971 and had a total airframe time of 4,905 hours 16 minutes and 1 hour 30 minutes since the last inspection.
Damage assessment by an authorized maintenance organization revealed: damaged hinge bearings and broken attachment fittings of the horizontal stabilizer; scratched paint on both sides of the fin; and damaged upper skin edges at the cutout. The glider also had a broken left wingtip wheel, a torn landing gear brake cable, and abrasions on the forward fuselage. The elevator was torn from its hinges due to impact of the tail section with the ground. The glider required repair by a maintenance organization. No damage occurred to airport property.
Meteorological Conditions
According to the Czech Hydrometeorological Institute weather assessment for LKCR at the time, the sky was partly cloudy with 3-4/8 cumulus clouds, base approximately 1,300 ft AGL. Temperature was 19–20 °C, visibility greater than 10 km. Wind was from 140° to 180° at 8–14 knots with gusts of 16–22 knots. The atmosphere was unstable, with transient gusty wind and light-to-moderate mechanical turbulence near the surface.
Analysis
During the takeoff roll, the glider pilot was unable to maintain directional control using rudder inputs, allowing the glider to deviate. After becoming airborne, the pilot failed to keep the glider level, and the right wingtip contacted the tall grass at the runway edge. The pilot attributed the accident to a yawing moment resulting from a combination of wind gust, limited rudder effectiveness at low speed, and the towline attachment at the center of gravity, which he could not counteract in time to prevent the rotation and subsequent ground impact. Visible damage was consistent with forces from the wingtip striking vegetation and the tail striking the ground.
Conclusions
The investigation determined that the pilot was qualified for the flight, the glider had a valid airworthiness certificate and was normally controllable, but the pilot failed to maintain correct alignment during the takeoff roll in crosswind conditions. The takeoff began in an uncoordinated manner, and after release, the wing caught tall grass. The impact induced a yawing moment that caused the tail to strike the ground, damaging the elevator attachments. The pilot was uninjured.
Probable Cause
The accident was caused by loss of control during the takeoff roll in aerotow in crosswind conditions.