Accident Overview
On September 7, 2024, at approximately 1030 mountain daylight time, a Taylorcraft BC12-D airplane, registration N95078, sustained substantial damage during an accident near Trojan, South Dakota. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot and passenger were not injured.
Sequence of Events
The pilot reported that while en route, the engine experienced a partial loss of power. He attempted to restore power by applying carburetor heat, adjusting the mixture, and checking the fuel control valve. These troubleshooting efforts were unsuccessful, and the airplane could not maintain altitude. The pilot descended into a wooded valley and conducted a forced landing into the treetops. The airplane came to rest inverted and sustained substantial damage to the fuselage and both wings.
Postaccident Examination
Examination of the wreckage revealed that the hold-down nuts on the right magneto were loose, allowing the magneto to rotate freely by hand. A lead deposit was noted in the No. 1 cylinder top spark plug, but it did not inhibit the spark plug's function. No other preimpact mechanical malfunctions were identified.
Maintenance History
A review of the airplane maintenance logbooks indicated that the last 100-hour inspection of the engine occurred on October 6, 2023. That inspection included timing the magnetos and cleaning and gapping the spark plugs. The last annual inspection was conducted on September 1, 2024, six days before the accident. According to the mechanic who performed that annual inspection, the ignition timing was checked, but he did not recall adjusting the magnetos. The airplane had operated approximately 5 to 10 hours between the annual inspection and the accident.