On May 26, 2002, at 1024 eastern daylight time, a homebuilt Barnett J4B-2 gyrocopter, N8121M, was substantially damaged during a landing at Central Jersey Regional Airport (47N), Manville, New Jersey. The certificated private pilot/owner received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. A pilot-rated witness stated that he watched the gyrocopter as it flew traffic patterns around the airport, and on the accident flight. He observed the flight of the gyrocopter from the parking ramp as he secured an airplane. During the last approach, the gyrocopter approached the grass area adjacent to runway 25 during an "odd, step-down" approach. The gyrocopter leveled off at 200 feet, reduced power, dove down and leveled off at 100 feet, reduced power, then leveled off at 50 feet. The last time the power was reduced, the gyrocopter pitched to a nose-down attitude and flew straight into the ground with no landing flare. The witness described the engine noise as "solid", with no sputtering or missing. A second witness said he had seen the gyrocopter perform takeoffs, landings, and traffic-pattern flights earlier in the day, and was walking out to his airplane when he noticed the gyrocopter approach the grass for a landing. The gyrocopter crossed abeam the landing threshold of the runway about 200 feet above the ground. The approach was fast, and the gyrocopter landed down at the departure end of the airfield. The gyrocopter rolled over as soon as it made contact with the ground. When asked about the sound of the engine, the witness said it sounded "fine." According to a third witness, who managed the local flight school, the gyrocopter had flown the length of the field at low altitude, landed, and taxied back several times prior to the accident. He did not see the accident flight, but heard the gyrocopter make contact with the ground. He then drove to the accident site to assist the pilot. The pilot had performed taxi tests of the gyrocopter during the weekend. When asked if they were post-maintenance tests, he said no. According to the pilot, he was conducting taxi tests on Saturday and Sunday. He had never really flown the gyrocopter before, and was in the process of getting it ready to fly. He added that he didn't mean to get airborne during the tests. On the last run, he took off on runway 25, but didn't think there was enough room to land, so he decided to go around. He flew crosswind, downwind, and base-to-final legs. When the pilot was asked if he was aligned with the paved runway when he turned from base leg to final, he replied that when he completed the turn, he was aligned with the grass apron, and elected to continue on his heading to land on the grass adjacent to the runway. When he did, he touched down in a hole, or he bounced, and the gyrocopter rolled over. When asked about the performance and handling of the gyrocopter, the pilot said, "It was very, very good." The gyrocopter was examined at the scene by Federal Aviation Administration inspectors. One of the inspectors stated that there were no mechanical anomalies. The pilot held a private pilot certificate with an airplane single engine land rating. He did not possess a rating or a student endorsement for rotorcraft/gyrocopter. The pilot reported about 200 hours of total flight experience, none of which was in the accident gyrocopter. He added that he had flown an ultra-light gyrocopter for about two years. The weather reported at Somerville, New Jersey, about 7 miles northwest of Manville, included calm winds with 9 miles of visibility.