On September 19, 1999, about 1306 Eastern Daylight Time, a Boeing Stearman PT-17, N29743, was substantially damaged during landing to a private grass strip in Westminister, Maryland. The certificated private pilot was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the flight which originated at the Montgomery County Airpark Airport (GAI), Gaithersburg, Maryland. The personal flight was conducted under 14 CFR Part 91. The pilot stated he landed on the grass strip, to the northwest. While taxiing to a hangar, the airplane contacted a hole and the pilot "over applied the brakes." The propeller then struck the ground and the airplane flipped over. The pilot exited the airplane and later turned it upright using cranes provided by the owner of the property. The pilot reported that a gravel road intersected the grass strip at its midpoint. The strip sloped uphill about 7-8 degrees, toward the road, and downhill about 12-13 degrees beyond the road. According to a Federal Aviation Administration Inspector, examination of the grass strip revealed tire tracks across the gravel road, similar to those of airplane tire skid marks. The tracks stopped at the point where the airplane came to rest, about 100 feet past the intersecting road, on the 1,500 foot long grass strip. Upon visual inspection of the airplane, the Inspector found that the vertical stabilizer and rudder were crushed; however, one wooden strut from the vertical stabilizer remained upright and extended from the fuselage about 2 1/2 feet. The horizontal stabilizer and elevator were undamaged, and three out of four of the wing struts were bent. The wooden propeller was damaged at both tips and was splintered throughout the length of the blade. The grass strip was not approved for airplane use by the Federal Aviation Administration (FAA); however, the pilot reported he had landed there in the past. The winds reported at an airport about 25 miles from the accident site, were from 160 degrees at 7 knots.