Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for Bell Helicopter Textron, Inc. (Bell), Model 412 and 412EP helicopters. This proposed AD is prompted by reports of cracking in the swashplate outer ring assemblies (outer ring). This AD would establish a lower life limit on certain outer rings, requiring a revision of the retirement life on the components' history card or equivalent record, and a revision of the maintenance manual or Instructions for Continued Airworthiness (ICA). This proposal also would prohibit installing these outer rings on any helicopter. The proposed 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.