What happened
During a takeoff attempt from runway 28 at Bergsetth Field, the towline of a glider unexpectedly released from the Piper PA-18 tow plane. The disconnection occurred approximately 200 feet above ground level (AGL) shortly after takeoff. Following the unscheduled release, the glider pilot attempted a right turn to return to the departure runway. During this maneuver, the glider pitched down and became unresponsive to control inputs, leading to an impact with trees and terrain.
This event marked the second unsuccessful launch attempt of the day. An earlier attempt had also resulted in an unscheduled release immediately after the tow was initiated. Following that first failure, a field manager reconnected the towline to the Piper PA-18 for a second attempt. In both instances, the towline detached from the release hook on the tow aircraft but remained connected to the latching mechanism on the glider.
The investigation
Investigators examined the tow-hitch mechanism located on the floorboard of the forward cockpit of the tow plane. The system operates by moving a handle from a forward position to an aft position to open the hitch. The pilot of the tow plane stated that the handle remained in the forward position and had not been moved during either release. Postaccident examination and testing of the tow-hitch revealed no discrepancies or anomalies that could account for the premature releases.
Additionally, the glider pilot noted in a written statement that he had not received a briefing regarding potential emergency landing sites near the field. He indicated that had such a briefing been provided, he would have chosen to fly to an alternative site given his altitude at the time of the release.