Amateur-built HELICYCLE N143PG accident near Mesa, Arizona

Probable cause

The pilot's failure to properly install and secure the wire connecting the electronic speed controller unit to the fuel controller actuator motor, which resulted in the wire’s disconnection in flight and the resultant partial loss of engine power.

NTSB analysis

The pilot reported that while in cruise flight the helicycle's engine lost partial power. Unable to maintain altitude he maneuvered to find a safe landing area, and autorotated onto a residential street. A witness reported that before the helicycle landed, it was oscillating and sounded as if the engine was cutting in and out. Postaccident examination of the helicycle revealed that the "B" wire, which runs between the electronic speed controller unit and fuel controller actuator motor, separated from the connection during cruise flight. The pilot reported that if the fuel controller actuator motor loses power, the engine would automatically go to a minimum fuel stop position and flight idle. The pilot further reported that there were no parts failures, but that he had installed the "B" wire without an additional strain relief at the connector, which allowed the wire to disconnect from the system during normal operations. The pilot reported that the accident can be prevented by installing a second parallel wire between the fuel controller actuator motor and the electronic speed controller unit.

Text from the NTSB. Open the NTSB docket for WPR13LA099 for the full record.