On April 28, 1984, an American Aviation Corp. (aac) AA-1A (registration N9391L) was involved in an aviation accident near Lake Harbor, FL. Investigators recorded the probable cause as: The failure of the engine mixture control cable, which resulted in an in-flight loss of engine power and a subsequent forced landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A forced landing occurred in a sugar cane field after the pilot adjusted the engine mixture, which killed the powerplant. Investigation revealed the mixture control cable had snapped despite recent replacement.
What happened
During the descent from 2500 feet mean sea level, the pilot made two adjustments to the engine mixture control. The second adjustment resulted in an immediate loss of engine power, necessitating a forced landing in a nearby sugar cane field.
The investigation
A post-accident examination of the aircraft revealed that the engine mixture control cable was broken. Records indicated that a replacement cable had been installed only 89 flight hours prior to the incident, in compliance with Airworthiness Directive AD-75-09-07.
Findings
The mechanical failure of the mixture control cable directly caused the loss of engine power during the critical phase of descent. The recent installation of the replacement component suggests a potential manufacturing defect or improper installation procedure, as the part failed well before its expected service life.
Probable cause
The failure of the engine mixture control cable, which resulted in an in-flight loss of engine power and a subsequent forced landing.