This January 2008 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Piper Cherokee Six. Location: Wiggins, Miss. Injuries: None. Aircraft damage: Substantial.
What reportedly happened: While in cruise flight the airplane’s engine lost power. The pilot attempted to troubleshoot the problem but was unsuccessful. Unable to maintain altitude, he executed a forced landing in a field. During the landing roll, the airplane nosed over.
During the post-accident examination of the engine, it was discovered that a brass hex plug, a component of the fuel injector servo, was hanging loose from its safety wire.
The gasket, found between the brass hex plug and the aluminum regulator cover, had softened due to engine heat. This allowed the brass hex plug to vibrate, back off and eventually fall out. This resulted in the partial loss of engine power. As a result of this investigation, the fuel servo manufacturer issued Mandatory Service Bulletin PRS-107 and the FAA issued Emergency Airworthiness Directive 2008-06-51.
Probable cause: The failure of the fuel servo gasket and subsequent partial loss of engine power.
For more information: NTSB.gov