What happened
On June 13, 2011, a Rolladen-Schneider LS 4-b glider was performing a winch launch from the grass runway 23 at the Porta Westfalica airfield (EDVY). During the takeoff roll, the pilot retracted the landing gear after approximately 40 to 50 meters of travel. The aircraft then proceeded to skid on its fuselage for about 23 meters before lifting off. The pilot reported hearing a rattling noise during this phase.
Following the retraction of the landing gear, the launch director issued a "Halt-Stopp" command to the winch operator via telephone. In response, the winch operator reduced engine power to idle and braked the cable drum. As the glider transitioned into a full climb, the pilot noticed a rapid decrease in airspeed. In an attempt to maintain flight, the pilot pushed the control stick forward; however, the aircraft lacked sufficient altitude and airspeed to maintain a glide or execute a recovery, resulting in a hard landing. The aircraft slid 26 meters after impact, coming to rest 200 meters from the start point and 8 meters off the grass runway. The accident resulted in one person slightly injured and heavy damage to the aircraft.
The investigation
The BFU examined the aircraft, the launch procedures, and the communication between the ground crew. The investigation noted that the landing gear lever was found in a middle position, and the landing gear doors were damaged. Structural damage to the Rolladen-Schneider LS 4-b was extensive, including longitudinal cracks in the fuselage skin, a broken fuselage tube near the tail attachment, and fabric tears on the left wing root and trailing edge.
Investigators also reviewed the operational procedures, noting that the launch director communicated the abort command to the winch operator via a direct telephone link, a communication channel to which the pilot was not included. The investigation also referenced the aircraft's manual, which advises that in winch launches, the landing gear should only be retracted after releasing from the cable, as the center of gravity coupling is attached to the gear.