The pilot was stock-spotting with both side windows of the aircraft open. He noticed smoke trailing from the aircraft, and saw that some towelling material and a chamois were smouldering under the rear seat. He closed the windows to reduce the flow of air to these articles and proceeded to select a suitable landing area. In the meantime, smoke in the cabin forced him to open a side window again, resulting in the smouldering material bursting into flame. He attempted to douse the flames with water from his water bottle with little success. During the landing on a flat-topped hill, he had to keep his head out the window for visibility. The aircraft bounced several times and overturned. The pilot was knocked unconscious for a period of about five minutes. When he regained consciousness he released his harness and extinguished the remnants of the fire with the aircraft's extinguisher. He believes the loose extinguisher struck him on the head during the overturn sequence. This accident was not the subject of an on-site investigation.
