Accident Overview
On June 21, 2023, at approximately 1330 central daylight time, a Champion 7EC airplane, registration N80461, sustained substantial damage during an accident near Waunakee, Wisconsin. The pilot and one passenger sustained minor injuries. The airplane was operated under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Preflight and Departure
The pilot had purchased the airplane earlier that day and planned to fly it to Brennand Airport (79C) in Neenah, Wisconsin. A mechanic had completed an annual inspection on the morning of the accident. At Waunakee Airport (6P3), the pilot added 10.7 gallons of 100 low-lead fuel. During the preflight inspection and engine runup, no anomalies were noted.
Loss of Engine Power
During the initial climb from runway 9, the pilot observed a decrease in engine rpm. He was unable to maintain altitude and could not identify the cause of the partial power loss. Shortly thereafter, the engine experienced a total loss of power, prompting the pilot to execute a forced landing. Upon touchdown on a residential road, the airplane struck a tree and an unoccupied motor vehicle. The airplane came to rest upright in the rear of another unoccupied motor vehicle. The two occupants egressed without further incident, and no persons on the ground were injured. The airplane sustained substantial damage to the right wing and fuselage.
Postaccident Findings
Examination revealed a manually operated Kohler fuel primer pump (part number K-2406-2, no serial number) was extended and unlocked, and would not lock. After use during engine start, the pump should be secured and locked. All spark plugs were carbon-fouled, consistent with a rich mixture condition.
A laboratory examination of the fuel primer pump showed a cylindrical pin perpendicular to the piston's axis, intended to lock the piston when fully inserted. The locking pin was about 0.093 inches in diameter. Normally, the pin is kept captive by a retention lip on the pump housing end cap when the piston is fully inserted and turned left or right. The end cap's retention lip was worn away around most of its circumference, leaving only a 0.143-inch section.
Fuel System Documentation
Champion 7EC fuel system installation drawings #7-796 and #7-10002 (in the Champion 7EC Operating and Service Manual) specify a Kohler fuel primer pump (part number K-2406-2). However, the manual does not list continued airworthiness guidance for the pump. The FAA Aviation Maintenance Technician Handbook - Airframe (FAA-H-8083-31B) describes how a manually operated fuel primer pump works, but FAA Advisory Circular 43.13-1B provides no inspection guidance for such pumps. During the investigation, the FAA attempted multiple times to contact Kohler without response, and a search for airworthiness information on the pump yielded no documents.