On July 17, 1991, an Aeronca 7AC (registration N84903) operated by Kent Sherman was involved in an aviation accident near Chataniak Vly, AK. Investigators recorded the probable cause as: PARTIAL LOSS OF ENGINE POWER FOR AN UNDETERMINED REASON. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot reported an engine problem during takeoff, forcing a landing off the lake. Investigation found no mechanical failure but a mislabeled fuel selector valve; center 'Main' position was actually 'Off'. Automotive fuel was used without a supplemental type certificate.
Incident Summary
The pilot-in-command reported that an engine problem occurred during the takeoff. As a result, he was forced to execute a landing off the lake.
Aircraft and Engine Examination
Investigators examined the airplane and performed a test run of the engine. The examination and test run did not reveal any reason for a mechanical failure of the engine.
Fuel Selector Valve Issue
During the investigation, it was discovered that the fuel selector valve was mislabeled. The valve had a center position that was labeled "Main," but this position was actually an "Off" position. It was not possible to determine the position of the fuel selector valve during the takeoff and the subsequent crash sequence.
Fuel Type
The aircraft was using automotive fuel. This fuel was not approved under a supplemental type certificate.