Accident Overview
During a night departure from an airport, the airplane's engine suffered a total loss of power. The pilot attempted to restore engine power but was unsuccessful, subsequently executing a forced landing to a field. The forced landing resulted in substantial damage to the airplane.
Investigation Findings
Examination of the engine revealed no preimpact mechanical malfunctions. However, inspection of the exhaust system uncovered that a portion of the internal baffle in the muffler assembly had separated from the surrounding structure. This loose baffle was free to move inside the muffler.
The investigation further noted that the tailpipe was equipped with an arch-shaped standoff assembly designed to prevent a loose exhaust baffle from covering the inboard end of the tailpipe. This standoff extended from the inboard end of the tailpipe and protruded into the muffler.
Alignment Issue
Examination of the alignment holes on both the tailpipe and muffler showed that when both holes were aligned, the standoff assembly did not protrude far enough into the muffler to keep the loose portion of the baffle from blocking the tailpipe.
Maintenance History
The airplane was manufactured in 1973. An overhauled tailpipe was installed at 4510.77 total hours of operation. The manufacturer recommended that the entire exhaust system, including heat exchange shroud, muffler, muffler baffles, stacks, and all exhaust connections be rigidly inspected at each 100-hour inspection. Additionally, it was recommended that all airplanes be fitted with a new muffler at or near 1,000 hours of use. The airplane's most recent 100-hour inspection was completed on March 31, 2005, at 5574 total hours. At the time of the accident, the airplane had operated 76.14 hours since that inspection.