Summary
We propose to supersede an existing airworthiness directive (AD) for Bell Model 214B, 214B-1, and 214ST helicopters with certain tail rotor hanger bearings (bearing) installed. The existing AD currently requires inspecting the bearing to determine whether an incorrectly manufactured seal material is installed on the bearing. Since we issued that AD, we have determined that replacing the defective bearing is a required terminating action. This proposed AD would retain the repetitive inspection of the bearings and would also require replacing the defective bearings. The proposed actions are intended to prevent loss of bearing grease, failure of the bearing, and subsequent loss of control of the helicopter.