What happened
On August 16, 1997, at a grass airfield near Großrückerswalde, Germany, a PZL-104 Wilga 35 was performing a glider tow operation. At approximately 16:04 local time, a glider had just completed a winch start and was being retracted. Simultaneously, the pilot of the PZL-104 Wilga 35 initiated a takeoff for a subsequent tow of a SZD-50-3 Puchacz glider.
During the initial climb, at an altitude of approximately 40 to 50 meters, the aircraft collided with the winch cable that was being retracted following the previous glider's release. The cable had drifted into the aircraft's path due to wind conditions. The impact caused significant damage to the propeller and the right wing, leading to a fuel leak. The pilot experienced severe engine vibrations and attempted an emergency landing in a nearby field. During the landing, the landing gear collapsed, causing the aircraft to overturn and catch fire. The pilot sustained serious injuries and managed to escape the burning wreckage, but a female passenger, who had been taken on board as a non-essential occupant, was killed in the fire.
The investigation
The BFU investigation reconstructed the sequence of events using witness statements, the pilot's testimony, and on-site findings. The investigation focused on the takeoff sequence, the visibility of the winch warning light, and the communication between the takeoff leader and the pilot. Investigators examined the pilot's flight experience and certifications, noting that while he was experienced with the aircraft type, his license lacked the specific endorsement required for towing gliders. The investigation also reviewed the airfield's operating procedures regarding simultaneous winch and tow operations.
Findings
- The pilot performed the takeoff under unauthorized conditions, as the airfield's procedures prohibited motorized aircraft from taking off while the yellow winch warning light was active.
- There was a discrepancy between the takeoff leader's report and the pilot's claim regarding whether takeoff clearance had been granted.
- The takeoff leader and flight controller failed to use available radio communication to instruct the pilot to abort the takeoff.
- The collision was caused by the aircraft striking the winch cable, which had drifted into the runway path due to wind.
- The pilot was operating without the required towing endorsement in his license documentation.
- The presence of an unauthorized passenger contributed to the fatal outcome.