Final Report: Faulty maintenance cited
Bell 47G-3B-2, Lafayette, Ind., July 24, 2008–A fatigue fracture of the carburetor heat control valve spring and inadequate maintenance inspection by the pilot/ mechanic caused the loss of engine power and subsequent crash of the Bell 47, according to the NTSB. The spring had had 832 hours in service. An additional cause was the low altitude of the operation, an aerial application run. The pilot, who was not injured, was also a certified mechanic who had performed maintenance on the helicopter, which was substantially damaged in the accident.