Incident Overview
According to a witness statement, a tow plane and its attached glider encountered a dust devil at an altitude between 100 and 200 feet above ground level. The witness observed the glider gain altitude above the tow plane, causing the tow rope to form a 30- to 45-degree angle. Subsequently, the nose of the tow plane dropped and the aircraft descended to the ground.
Tow Rope Separation
Examination of the tow rope revealed that it had separated aft of the tow plane's tow ring. The portion of the rope with the tow ring attached was located near the aircraft. The remaining length of the rope, with the glider's tow ring attached, was found farther back along the flight path. The separation point was consistent with a break in the rope behind the tow plane's attachment point.
Hook Release Mechanism Inspection
An inspection of the tow plane's hook release mechanism determined that it was in the open position. Investigators concluded that the mechanism had opened upon impact. This conclusion was based on the separation of the tow rope, the proximity of the rope to the tow plane hook, and the apparent snap-back of the remaining rope away from the crash site.
Summary
The encounter with the dust devil led to an abnormal flight attitude, followed by a descent of the tow plane. The tow rope separated during the event, and the hook release mechanism was found open after the impact. No further details about the flight or the aircraft were provided in the source.