Summary
We are revising an earlier proposed airworthiness directive (AD) for Bell Helicopter Textron, Inc. (Bell), Model 214B and B-1 helicopters, which proposed to require inspecting certain pylon support spindle assemblies (spindles) for any corrosion, or a nick, scratch, dent, or crack, and repairing or replacing any unairworthy spindle before further flight. This SNPRM proposes to revise those requirements by updating the cost of compliance, revising the recording requirements, adding a requirement to reduce the retirement life of an installed spindle, and adding Bell Model 214ST to the applicability.