On October 26, 1996, at 1655 hours Pacific daylight time, a Luscombe 8A, N71643, was substantially damaged during a collision with the ground following takeoff on runway 27L at Gillespie Field, El Cajon, California. The private pilot and one passenger were not injured. Visual meteorological conditions prevailed for the local area personal flight. The pilot reported that he had completed four touch-and-go landings on runway 27L. Winds were aligned with the runway at about 12 knots and there was no turbulence present while he flew in the airport traffic pattern. The aircraft was climbing out after the fourth touch-and-go, and had reached about 250 feet agl at midfield, when the pilot observed a dust devil and debris blowing across the departure end of the runway. As the aircraft approached the departure end of the runway, he felt the aircraft's wings rock like a wake turbulence encounter. In the next few seconds the aircraft started descending at about 500 feet per minute, although he had full throttle applied and was in climb attitude at 70 miles per hour. He tried to turn back to the parallel runway 9L, but collided with terrain in an open dirt area about 500 feet west of the runway threshold. He estimated that from the time he felt the wings rock until he was on the ground was no more than 10 seconds. He added that there were no mechanical problems with the aircraft. Gillespie tower personnel reported to a San Diego Flight Standards District Office inspector that after the accident there had been freak wind gusts up to 50 knots that lasted 2 to 3 minutes, followed by calm wind conditions.