On June 13, 1999, about 1642 Eastern Daylight Time, a homebuilt RV-6, N81081, was substantially damaged during a landing at Greensburg Jeannette Regional Airport, Jeannette, Pennsylvania. The certificated private pilot and pilot rated passenger were not injured. Visual meteorological conditions prevailed for the flight that originated from the Mount Pleasant/Scottdale Airport, Mount Pleasant, Pennsylvania. No flight plan was filed for the personal flight conducted under 14 CFR Part 91. The pilot reported that he was performing a simulated forced landing to Runway 20. On short final approach, with idle power, the airplane experience a downdraft. The pilot added power, but the left wing struck a small hill located at the approach end of the runway, and the airplane came to rest on the runway. Examination of the wreckage by a Federal Aviation Administration Inspector did not reveal any pre-impact mechanical malfunctions, nor did the pilot report any. The Inspector observed structural damage to both wings and the fuselage. At an airport approximately 13 miles away, at 1653, the reported winds were from 160 degrees at 5 knots.