Casualties unknown

Forced Landing Following Engine Power Loss After Maintenance Check Flight (N123JB)

Vernon Hills, IL, US

On April 18, 1991, a Beech 35-A33 (registration N123JB) operated by G & N Aircraft was involved in an aviation accident near Vernon Hills, IL. Investigators recorded the probable cause as: The pilot's failure to drain the main fuel tanks prior to flight, which resulted in water contamination of the fuel system and subsequent engine power loss. 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

A pilot conducting a maintenance check flight experienced engine power loss approximately 30 minutes after departure, resulting in an off-airport forced landing.

What happened

The pilot departed on a maintenance check flight following an engine overhaul. Approximately 30 minutes into the flight, the engine lost power, and the pilot made an off-airport forced landing.

The investigation

On inspection, water was drained from the main fuel tank(s). The pilot reported that he had drained the aux fuel tanks, but not the main tanks.

Probable cause

The pilot's failure to drain the main fuel tanks prior to flight, which resulted in water contamination of the fuel system and subsequent engine power loss.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X16743. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.