Primary finding
Probable cause
Maintenance personnel’s improper installation of an improperly sized clamp on the fuel supply line, which allowed air to enter the supply line, a subsequent loss of engine power, and a forced landing.
Investigator assessment
Analysis narrative
The pilot departed from a campground area in the single-engine experimental airplane. During the airplane’s initial climb, the engine lost power and the pilot made a forced landing into a cornfield, which substantially damaged both wing struts. Postaccident examination of the engine revealed a loose fuel supply line to the inlet fitting of the vacuum-driven fuel pump. Although the clamp on the inlet fitting was tightened to its maximum clamping position, it was not the correct size, and the fuel supply line was still loose in the fitting. Thus, it is likely that maintenance personnel did not ensure an airtight fitting with a properly sized clamp, which allowed air to enter the fuel supply line and resulted in a loss of engine power.
Source record
Factual narrative
On June 7, 2020, about 1513 eastern daylight time, a Team Mini-Max 1600R airplane, N827WS, was substantially damaged when it was involved in an accident near Marshall, Michigan. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, the engine lost total power during initial climb after departing from a campground area. The pilot made a forced landing into a cornfield, which damaged both wing struts. During the flight prior to the accident, the pilot noticed engine roughness that discontinued after he turned the fuel pump on. The pilot inspected the airplane after landing but was not able to find a rationale for the engine roughness. Following the accident, examination of the engine revealed that the fuel supply line to the inlet fitting of the vacuum driven fuel pump was loose on the fitting. Although the clamp on the inlet fitting had been tightened to its maximum clamping position, the fuel supply line was still loose on the fitting and without a proper seal it was possible for air to enter the fuel system.