19980825021859A

Acft crashed on landing under unknown circumstances. (-23) on August 25, 1998, at approximately 1600 CDT, an experimental-amateur built, twin-star gyroplane, N72DE, received substantial damage as a result of an accident at the farrington airpark, Paducah, KY. The aircraft piloted by an airplane rated private pilot who possessed a solo endorsement for gyroplanes, was executing a normal approach to landing on runway 22. According to the pilot's statement, at approximately 15 feet and 60 knots IAS above the runway, the aircraft went into an uncommanded 185 degree right turn before coming to a rest in the sod adjacent to the runway 22 landing threshold. Information gathered from the investigation appears to indicate that a bolt (an type) with a locking nut failed, thus separating the right pitch horn from the yoke assembly. Maintenance records indicate that the aircraft underwent a condition inspection iaw with 14 CFR 43 appendix d and was returned to service on August 13, 1998. There were no indications from the maintenance records, or from maintenance personnel that work was performed on the pitch horns or yoke assembly previous to the accident. The pilot received no injuries and there was no post crash fire. Weather at the time of the accident was VFR with winds from 240 degrees at 6 knots. (.4) the gyroplane was on short final, about 15 feet above the ground, when it went into an uncommanded right turn and right roll. The heading changed 180 degrees, and the gyroplane impacted sod near the runway threshold. The gyroplane had a rotor brake mechanism which was activated by pushing the cyclic control full forward. A through-bolt which had attached the two lateral control arms to the yoke assembly, was discovered missing, and the right lateral control arm had separated from the yoke assembly. The kit manufacturer was considering implementing a clamp-type rotor brake system, much like a bicycle's, to prevent rotor brake forces from passing through the flight control system.