On July 31, 1982, a Bellanca 7KCAB (registration N57507) operated by Gerald S. Grant was involved in an aviation accident near Agawam, MA. Investigators recorded the probable cause as: The engine's failure to maintain idle RPM due to a fuel injector delivering below-specification fuel flow at idle settings. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft experienced an unexpected engine shutdown while configuring for landing on runway 23. The pilot lost power and crashed into a wooded area approximately one-quarter mile from the runway end.
What happened
The pilot was in the process of setting up to land on runway 23 when the engine suddenly quit. As the aircraft descended, it impacted a wooded area located approximately one-quarter mile from the end of the runway.
The investigation
Following the accident, investigators conducted a post-accident engine run to determine the mechanical cause of the shutdown. During this test, the engine failed to maintain the manufacturer's recommended idle speed of 700 RPM. Instead, the RPM dropped significantly to 250 before the engine finally stopped completely.
A flow check of the fuel injector revealed that it was delivering 3 PPH (pounds per hour) less than the required specification at the idle setting. To correct this deficiency, the idle adjusting wheel was turned approximately two and a half turns, which brought the fuel flow back up to the proper specifications.
Probable cause
The engine's failure to maintain idle RPM due to a fuel injector delivering below-specification fuel flow at idle settings.