Amateur-built KITFOX V VIXEN N52367 accident near Caldwell, Idaho

Probable cause

The partial loss of engine power due to a loose wire leading to the engine’s electronic control unit (ECU). Contributing was the pilot’s exceedance of the critical angle of attack while maneuvering, which resulted in an aerodynamic stall at an altitude too low for recovery.

NTSB analysis

The pilot planned to take off and remain in the traffic pattern as part of a post-maintenance test flight of the airplane. After climbing to about 200 ft above the runway, the engine started to gradually lose power to about 15-20% engine power. The pilot had begun maneuvering the airplane for a forced landing when it entered an aerodynamic stall. The pilot attempted to recover from the stall; however, the airplane impacted terrain and nosed over, which resulted in substantial damage to the fuselage, left wing, wing struts, and empennage.

Postaccident examination determined that the power supply wire for the experimental engine’s electronic control unit (ECU) was loose in the crimped terminal. It is likely that during the flight, the intermittent power source to the ECU activated the engine’s “limp mode,” which resulted in a reduction of engine power to a level that was insufficient to maintain altitude. The engine’s limp mode is a safety feature designed to protect the engine and powertrain in automotive applications.

Text from the NTSB. Open the NTSB docket for WPR22LA322 for the full record.