ERA11FA401 · Slingsby CAPSTAN TYPE 49B

According to the glider pilot/owner, he purchased the glider 1 week before the accident and flew it with the previous owner for about 1 hour at the time of purchase. He assembled the glider with the assistance of the tow plane pilot and completed all post-assembly checks before they were joined by his copilot. The pilot and copilot then performed the before-takeoff checks outside the aircraft, confirmed operation of the tow release mechanism, and verified that the spoilers were closed. During the initial climb, the glider pilot noticed that the glider was not climbing, and he and his copilot, a more experienced glider pilot, discussed relative position to the tow plane in order to avoid wake turbulence and improve climb performance. About 200 feet above ground level and over the trees beyond the departure end of the runway, the glider pilot observed the tow plane's rudder "waggle" back and forth, and his copilot shouted, "Release! Release! Release!" The glider pilot released the glider from the tow plane and entered a left turn to the north for a forced landing on the divided highway east of the airport. The copilot joined him on the flight controls before the glider overshot the highway and collided with trees on the east side of the roadway.

The tow plane pilot provided a similar recounting of the events. He explained that, before the flight, the proper signals for “too fast” or “too slow” were discussed but no others. He added that he had discussed signaling with the glider’s copilot many times previously but that they had not recently discussed the rudder-wag signal, which means “check spoilers.” After takeoff, he noted that the tow plane’s performance was as expected, but the climb rate was not. He checked the glider in his rearview mirror and noted that the spoilers were deployed. The tow plane pilot provided the internationally recognized (in the glider community) rudder-wag signal, and, instead of stowing the spoilers, the glider released from the tow.

Postaccident examination of the glider revealed no mechanical deficiencies. The pilot/owner stated that he knew the meaning of the rudder-wag signal, but responded to the callout from his copilot. He further stated that he believed the spoilers were stowed during preflight and before-takeoff checks, but he did not confirm that the control was locked in its detent prior to takeoff.

Verbatim NTSB analysis and probable cause from the NTSB dataset