Casualties unknown

1991-07-28: Beech C-23 (N7690R) — David J. Stoddard — Williamstown, MA

Williamstown, MA, US

On July 28, 1991, a Beech C-23 (registration N7690R) operated by David J. Stoddard was involved in an aviation accident near Williamstown, MA. Investigators recorded the probable cause as: The crankshaft gear retaining bolt backed out, resulting in disengagement of the crankshaft. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A private pilot experienced a complete loss of engine power at 3,000 feet after the crankshaft gear retaining bolt backed out, disengaging the crankshaft. The engine had recently been overhauled without following manufacturer's service instructions.

Incident Overview

A private pilot with 200 hours of flight experience encountered a complete loss of engine power while in cruise flight at an altitude of 3,000 feet. The engine failure was traced to the crankshaft gear retaining bolt, which had backed out, leading to the disengagement of the crankshaft.

Engine Overhaul Context

The engine had recently undergone an overhaul. However, the manufacturer's service instructions were not complied with during the overhaul process. This non-compliance was noted in the investigation.

Forced Landing Attempt

Following the loss of engine power, the pilot attempted to execute a forced landing. Suitable terrain was not available to the pilot to perform a successful forced landing.

Investigation Findings

The investigation determined that the engine failure was the direct result of the crankshaft gear retaining bolt backing out, which caused the crankshaft to disengage. The failure occurred despite the recent engine overhaul, during which the manufacturer's prescribed procedures were not followed.

Probable cause

The crankshaft gear retaining bolt backed out, resulting in disengagement of the crankshaft.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X17679. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.