Casualties unknown

Engine Power Loss Due to Crankshaft Idler Gear Failure During Low-Altitude Maneuver (N8927F)

Plainfield, IL, US

On September 15, 1987, a Hughes 269A (registration N8927F) operated by Harold E Miller was involved in an aviation accident near Plainfield, IL. Investigators recorded the probable cause as: The failure of a stud and bolt holding the crankshaft idler gear shaft in place, which caused the crankshaft idler gear to disengage from the crankshaft and camshaft main gears, resulting in a loss of engine power. 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 2026-06-10Data APIEditorial standards

While maneuvering at about 4 feet above ground level, the pilot experienced a loss of engine power, leading to an uncontrolled right turn and descent, resulting in collision with the ground.

Accident Summary

During a maneuver conducted at approximately 4 feet above ground level, the pilot encountered a sudden loss of engine power. The aircraft subsequently entered an uncontrolled right turn and descent, ultimately colliding with the ground.

Engine Failure Details

Investigation determined that the engine power loss was caused by the failure of a stud and bolt that secured the crankshaft idler gear shaft in place. This structural failure allowed the crankshaft idler gear to disengage from the crankshaft and camshaft main gears. Consequently, the engine lost its ability to transmit power, resulting in the loss of thrust.

Probable cause

The failure of a stud and bolt holding the crankshaft idler gear shaft in place, which caused the crankshaft idler gear to disengage from the crankshaft and camshaft main gears, resulting in a loss of engine power.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X32025. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.