On April 16, 1983, a Beech E-18S (registration N4980V) was involved in an aviation accident near Davis, CA. Investigators recorded the probable cause as: The backing out of the Stromberg carburetor float fulcrum screw, which was not safety wired, allowing fuel to escape into the exhaust area and cause a fire. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A fire broke out in the right engine area during a parachute jumping mission, forcing a precautionary landing. Investigation revealed a Stromberg carburetor float fulcrum screw had backed out.
What happened
During a flight dedicated to a parachute jumping mission, an engine fire erupted in the area of the right engine. The crew initiated a precautionary landing to address the emergency.
The investigation
A post-accident examination of the aircraft revealed that the float fulcrum screw on the Stromberg carburetor had backed out. This failure allowed fuel to escape into the exhaust area, creating the fire hazard. It was reported that the screw had not been safety wired, which likely contributed to its loosening.
Findings
The primary mechanical issue was the fuel leak caused by the displaced float fulcrum screw. The lack of proper safety wiring on this component allowed it to work loose during operation.
Probable cause
The backing out of the Stromberg carburetor float fulcrum screw, which was not safety wired, allowing fuel to escape into the exhaust area and cause a fire.