Incident Overview
A glider and its tow plane were involved in an incident during a tow operation. Both pilots had agreed beforehand that if the glider became airborne by midfield, the glider pilot would release the tow line. The takeoff proceeded normally, and the glider achieved airborne status before reaching midfield.
Tow Plane Encounter
However, the tow plane pilot encountered a wind gust or wind shear. This gust initially lifted the tow plane, then caused it to settle back toward the ground. Sensing that he was not accelerating and gaining altitude as expected, the tow plane pilot released the tow line.
Glider Pilot Actions
The glider pilot followed the tow plane to maintain proper tow position. As the tow plane climbed out, the glider pilot realized he had been released and observed his airspeed deteriorating. The right wing began to stall and drop. He attempted to land in an empty parking lot, but the right wing struck the railing of an observation deck.
Communication Issue
The tow plane pilot later stated that he failed to warn the glider pilot about the tow release because he assumed the glider pilot would see and feel the release. Additionally, he did not want to distract the glider pilot from flying the glider.