Amateur-built Kitfox N925DP accident near Clatskanie, Oregon

Probable cause

A partial loss of engine power due to an improperly secured throttle cable set screw.

NTSB analysis

The airline transport pilot of the experimental, amateur-built airplane reported that, while flying about 800 ft above a river during a personal flight, he advanced the throttle to climb then the engine started to lose power. He elected to land on a nearby island, during which the airplane nosed over.

Postaccident examination of the airplane revealed that the throttle cable set screw on the aft side of the throttle body arm had backed out of its original position and was no longer securing the throttle cable. As a result, the cable moved freely with no corresponding motion on the throttle body arm. This would have also resulted in the pilot's inability to adjust the engine power from the cockpit throttle control. Maintenance records revealed that the pilot built and installed the throttle body arm about 7 months and 204 flight hours before the accident. In addition, a vernier-style throttle cable was installed about 6 months and 159 flight hours before the accident. It is likely that the set screw was improperly secured during one of the previous maintenance events and came loose during operation, which released its hold on the throttle cable.

Text from the NTSB. Open the NTSB docket for WPR18LA111 for the full record.