On April 27, 1990, a Beech A23-19 (registration N5664S) was involved in an aviation accident near Apple Valley, CA. Investigators recorded the probable cause as: Water contamination of the fuel due to a deteriorated 'O' ring on the right fuel cap, which allowed moisture ingress during an aircraft wash. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft experienced a loss of power during the initial climb and crashed while attempting to return to the airport. Investigation revealed water in the right fuel tank.
What happened
The aircraft experienced a sudden loss of power during the takeoff initial climb phase. The pilot attempted to return to the airport but was unable to maintain flight, resulting in a crash.
The investigation
FAA inspectors examined the aircraft and its engine following the accident. No mechanical discrepancies were found with the engine itself. However, investigators discovered that the right fuel cap had a badly deteriorated 'O' ring seal. Upon inspection of the right fuel tank, water was found present inside. The fuel selector switch was positioned to draw from the right tank at the time of the incident.
Findings
Witnesses on the airport reported that the pilot washed the aircraft prior to the flight. This activity likely allowed water to enter the fuel system through the compromised seal on the right fuel cap, leading to water contamination in the fuel supply.
Probable cause
Water contamination of the fuel due to a deteriorated 'O' ring on the right fuel cap, which allowed moisture ingress during an aircraft wash.