Bell 47G-3B-2
Lafetyette, IN — July 24, 2008
Event Information
| Date | July 24, 2008 |
| Event Type | ACC |
| NTSB Number | CHI08CA210 |
| Event ID | 20080905X01388 |
| Location | Lafetyette, IN |
| Country | USA |
| Coordinates | 40.45945, -86.75361 |
| Highest Injury | NONE |
Aircraft
| Make | Bell |
| Model | 47G-3B-2 |
| Category | HELI |
| FAR Part | 137 |
| Aircraft Damage | SUBS |
Conditions
| Light Condition | DAYL |
| Weather | VMC |
Injuries
| Fatal | 0 |
| Serious | 0 |
| Minor | 0 |
| None | 1 |
| Total Injured | 0 |
Event Location
Probable Cause
The loss of engine power during an aerial application flight due to a fatigue fracture of the carburetor heat control valve spring and the inadequate maintenance inspection by the pilot/mechanic. An additional cause was the low altitude of the operation.
Full Narrative
The helicopter began losing engine power during an aerial application while maneuvering. The pilot attempted a landing in the field where the helicopter impacted terrain about 80 yards from an access road at the north edge of the field. The helicopter sustained substantial damage. The pilot was uninjured. Examination of the helicopter revealed that the carburetor heat control spring that keeps the carburetor closed was broken and its support rod had worn into the housing. The heat valve could only be opened about 1/3 and while corresponding cockpit control remained in the closed position. The fracture surface of the spring was consistent with fatigue. The spring accumulated a total time in service of 832 hours. The pilot was a certificated aircraft mechanic who also performed maintenance on the helicopter. A National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report was not received from the pilot.
About This NTSB Record
This aviation event was investigated by the National Transportation Safety Board (NTSB). NTSB investigates all U.S. civil aviation accidents to determine probable cause and issue safety recommendations to prevent future accidents.