On May 31, 1991, a Champion 7ECA (registration N9646S) operated by Blaine S. Blount was involved in an aviation accident near Quincy, FL. Investigators recorded the probable cause as: THE PILOT'S INADEQUATE PREFLIGHT INSPECTION AND THE BLOCKED VENT LINE. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Shortly after takeoff, an aircraft engine lost power. The pilot attempted to return to the airport, but the aircraft crashed. Post-crash examination revealed a clogged fuel tank vent line with an insect nest.
Accident
After departing from the airport, the aircraft's engine experienced a loss of power. The pilot initiated a return to the airport. While attempting to return, the aircraft crashed.
Investigation
A post-crash examination of the aircraft was conducted. This examination revealed that a fuel tank vent line was obstructed by an insect nest. No mechanical failures of the engine or airframe were identified. The aircraft's operating manual includes a preflight checklist that contains an item for checking the fuel vent line for obstruction. This checklist is part of Section III, which covers Normal Operating Procedures. The blockage of the vent line was found during the examination of the aircraft.