Airworthiness Directives; Bell Helicopter Textron, Inc.
We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron, Inc. (Bell), Model 412 and 412EP helicopters. This AD requires establishing a lower life limit on certain swashplate outer ring assemblies (outer ring), revising the retirement life on the components' history card or equivalent record, and revising the maintenance manual or Instructions for Continued Airworthiness (ICA). This AD also prohibits installing these outer rings on any helicopter. This AD was prompted by reports of cracking in the outer rings. The actions are intended to prevent failure of an outer ring because of cracking, which could lead to the loss of main rotor (M/R) blade pitch control and subsequent loss of helicopter control.