What happened
On July 7, 2023, at approximately 10:30 LMT, a private pilot was performing a recreational aero-tow flight near the Borsk airfield. The aircraft, an SZD-24-4A Foka 4 with registration SP-2418, was being towed by a vehicle using a 500-meter rope. While the initial takeoff roll and liftoff proceeded normally, witnesses noted that the subsequent climb was significantly slower than typical performance levels.
At an altitude of less than 100 meters AGL, the pilot released the towline. For approximately five seconds, the glider maintained a straight flight path. However, the aircraft then entered a right-hand turn with increasing bank angle. During this maneuver, the right wing struck the treetops, leading to structural failure and a subsequent impact with the ground. The pilot sustained fatal injuries at the scene, and the aircraft was destroyed.
The investigation
The PKBWL examined the wreckage and interviewed witnesses, including the tow driver and other pilots present at the airfield. The investigation focused on the aircraft's mechanical state following maintenance work performed by the pilot the previous evening. The pilot had reportedly disconnected various control linkages to prevent damage during storage. Investigators also reviewed the pilot's medical certification and flight experience, noting a valid license and a negative toxicology report.
Findings
- The primary cause of the accident was the loss of lateral control resulting from the left aileron drive being disconnected or improperly reconnected.
- The aircraft's climb rate was abnormally low during the tow phase due to this mechanical malfunction.
- The pilot had performed maintenance on the control surfaces the night before, which included disconnecting the pilot seat, floor, and cockpit covers.
- The impact with the trees and ground involved high inertial forces, making the accident unsurvivable.
- Weather conditions and the pilot's physiological state were not contributing factors to the crash.