The SD-1 Minisport is an ultralight single-seat aircraft of tailwheel layout and falls into the single-seat de-regulated (SSDR) category when operated in the UK.
After an uneventful takeoff and circuit, the aircraft was configured for landing and on final approach. The pilot reported that the IAS was steady at 60 mph and the groundspeed on his GPS showed a headwind of approximately 15 kt.
As the aircraft passed over the runway threshold it dropped unexpectedly, resulting in a heavy landing and associated damage. The pilot was uninjured. He reported that there was no surface wind when he exited the aircraft and he believed that windshear may have been a contributory factor in the accident.