NTSB Identification: ATL96LA068.
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Accident occurred Thursday, March 21, 1996 in GROVE HILL, AL
Probable Cause Approval Date: 04/03/1997
Aircraft: Bell 205A-1, registration: N68HJ
Injuries: 1 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
During an external lift operation to pick up a fertilizer bucket, the vertical fin separated from the tail boom. The helicopter rotated to the right, and the pilot tried to move away from obstacles. The tail boom struck the ground and separated from the fuselage, while the helicopter was still rotating to the right. The main rotor blades hit a tree and the helicopter came to rest on the ground on its left side. Investigation revealed a fatigue fracture through a rivet hole of the vertical fin forward spar. An inspection of this area was signed off the day prior to the accident. However, examination of the wreckage, and a sister ship, revealed that the fracture location could not be observed during normal inspections because of other structure. One airworthiness directive (AD), and service bulletins issued by the manufacturer, addressed vertical fin spar cracks, but none applied to this ship. The AD required removal of the rivet, where the fatigue fracture initiated, to facilitate inspection of the rivet hole. The inspection was no longer required after compliance with a service bulletin that modified the spar. This helicopter was modified during its original manufacture.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: fatigue failure of the vertical fin forward spar in an area that was not accessible to inspection. A factor relating to the accident was: guidance for inspection of the area (where the fatigue occurred) was insufficiently defined by the manufacturer. Full narrative available
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