Primary finding
Probable cause
The fracture and separation of a control rod in the cyclic flight control system.
Investigator assessment
Analysis narrative
While maneuvering at 700 feet agl, the pilot of the amateur-built helicopter felt something "break" and the fore-and-aft portion of the cyclic flight control system became inoperative (disconnected). He lowered the collective control, reduced engine power, and made a run-on landing in an open field. During the landing the toe of one skid "dug in" and the helicopter came to rest on its side. Postaccident examination revealed that a push-pull tube in the cyclic control system fractured circumferentially in the wall at one end near where a through-bolt attached the rod end fitting to the tube.
Source record
Factual narrative
On August 26, 2000, at 0906 hours Pacific daylight time, a Perrucci Revolution Mini-500 experimental helicopter, N7SZ, was substantially damaged during a forced landing near Gridley, California. The student pilot was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local area personal flight, which departed from the owner's property in Gridley about 0840. The amateur built helicopter was operated by the owner under 14 CFR Part 91. The pilot reported that, while making a turn at 700 feet agl, he felt something break and the fore-and-aft portion of the cyclic flight control system became inoperative (disconnected). He lowered the collective control, reduced engine power, and made a run-on landing in an open field. During the landing the toe of one skid "dug in" and the helicopter came to rest on its side. Postaccident examination revealed that a push-pull tube in the cyclic control system fractured circumferentially in the wall at one end near where a through-bolt attached the rod end fitting to the tube. The assembly was Revolution Helicopters part number 0165.