Airworthiness Directives; Bell Textron Inc. (Type Certificate Previously Held by Bell Helicopter Textron Inc.) Helicopters

The FAA is adopting a new airworthiness directive (AD) for Bell Textron Inc. (Bell) Model 214ST helicopters. This AD was prompted by the discovery of bolts with nonconforming external thread root radii. This AD requires removing the affected bolts from service and prohibits installing an affected bolt on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.