Accident Summary
A pilot intentionally executed a wheels-up landing after encountering a low voltage light and subsequent loss of engine power. The aircraft was not damaged by the landing beyond the expected consequences of such a maneuver.
Engine Examination
Post-accident examination of the engine revealed that the number 2 bearing and crankshaft had shifted forward. This shift led to the failure of the alternator drive shaft and other accessories, as well as damage to additional components of the power drive train.
Investigation of the engine also found adhesive (Permatex) applied to the crankcase halves surfaces, inside the seam face, and on the through-bolts. According to the manufacturer, the adhesive should only be used to hold the crankcase seam string in place. The excess sealant contributed to either a loss of torque or under-torquing of the through-bolts.
Maintenance History
The engine had accumulated 3,692 hours tachometer time at its overhaul in 1993, when the time between overhaul (TBO) was extended to 1,600 hours. In 2000, the engine had 1,108 hours since overhaul. At that time, six new "classic cast" cylinder assemblies, along with new pistons, rings, and piston pins, were installed. This work required separation of the crankcase. At the time of the accident, the engine had 5,435 hours tachometer time and 1,743 hours since the 1993 overhaul.