On November 6, 1989, a Bell 47G/TOMCAT MK5 (registration N73871) operated by Ag-rotor Inc was involved in an aviation accident near Elberton, GA. Investigators recorded the probable cause as: A LOSS OF ENGINE POWER DUE TO CARBURETOR ICE. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter crashed while performing a spraying mission for a federal boll weevil eradication program after the engine unexpectedly ceased operation.
What happened
The pilot was engaged in a spraying operation as part of a federal boll weevil eradication program. While approaching a cotton field at 500 feet AGL, an observer noted the helicopter began to turn away from the field. The aircraft then exhibited lateral wavering from right to left, followed by a loud noise and the immediate cessation of all engine noise. The helicopter appeared to fall straight down, with a crashing sound heard approximately five seconds later.
The investigation
Examination of the wreckage revealed that only small amounts of fuel remained in the engine and accessories, despite the flight having departed with approximately 25 gallons of fuel. Weather conditions at the time were noted as being conducive to carburetor ice, with a temperature of 74 degrees and a dewpoint of 60 degrees. The investigation found no evidence of an attempted autorotative procedure or any mechanical failure.