On July 1, 1984, an Aeronca 15AC (registration N1436H) operated by Howard Francis Bates was involved in an aviation accident near Ester, AK. Investigators recorded the probable cause as: Failure of a deteriorated oil outlet line from the oil cooler resulting in loss of oil and oil pressure. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft landed in spruce trees after the engine lost oil pressure due to a failed oil line. The pilot admitted postponing replacement of oil lines during the last annual inspection.
Accident Overview
The aircraft executed a forced landing into the tops of small spruce trees after the engine lost oil pressure and was subsequently shut down by the pilot.
Pilot Account
The pilot later admitted that the oil lines required replacement during the last annual inspection, which occurred on June 22, 1984. He postponed the replacement and later forgot to complete the maintenance in the excitement of resuming flight operations on floats after a two-year hiatus.
Mechanical Failure
Investigators determined that a badly deteriorated oil outlet line from the oil cooler had failed, resulting in the loss of engine oil and oil pressure. The failure of this component led directly to the loss of engine power.
Probable cause
Failure of a deteriorated oil outlet line from the oil cooler resulting in loss of oil and oil pressure.