2021-21050: Airworthiness Directives; Arrow Falcon Exporters, Inc. (Previously Utah State University); California Department of Forestry; Firefly Aviation Helicopter Services (Previously Erickson Air-Crane Co.); Garlick Helicopters, Inc.; Global Helicopter Technology, Inc.; Hagglund Helicopters, LLC (Previously Western International Aviation, Inc.); International Helicopters, Inc.; Precision Helicopters, LLC; Robinson Air Crane, Inc.; San Joaquin Helicopters (Previously Hawkins and Powers Aviation, Inc.); S.M.&T. Aircraft (Previously US Helicopters, Inc., UNC Helicopter, Inc., Southern Aero Corporation, and Wilco Aviation); Smith Helicopters; Southern Helicopter, Inc.; Southwest Florida Aviation International, Inc. (Previously Jamie R. Hill and Southwest Florida Aviation); Tamarack Helicopters, Inc. (Previously Ranger Helicopter Services, Inc.); US Helicopter, Inc. (Previously UNC Helicopter, Inc.); West Coast Fabrication; and Williams Helicopter Corporation (Previously Scott Paper Co.) Model AH-1G, AH-1S, HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P Helicopters; and Southwest Florida Aviation Model UH-1B (SW204 and SW204HP) and UH-1H (SW205) Helicopters

Summary

The FAA is withdrawing a notice of proposed rulemaking (NPRM) that proposed to supersede Airworthiness Directive (AD) AD 2002-20-01, which applies to certain Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH- 1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters; and Southwest Florida Aviation Model SW204, SW204HP, SW205, and SW205A-1 helicopters, manufactured by Bell Helicopter Textron, Inc. (BHTI) for the Armed Forces of the United States. The NPRM would have required removing certain serial-numbered tension-torsion (TT) straps from service, reducing the retirement life for other TT straps, and establishing a retirement life in terms of calendar time in addition to hours time-in- service (TIS) for certain other affected TT straps. The NPRM also would have added two model helicopters to the applicability of the AD. The NPRM was prompted by fatigue cracking in certain TT straps that have stainless steel filament windings and a determination that corrosion damage, which is related to calendar time, necessitated a calendar time retirement life for certain TT straps in addition to the retirement life based on hours TIS. The NPRM was also prompted by fatigue cracking in other TT straps with encased thin stainless steel plates. Since issuance of the NPRM, the FAA has re-reviewed the available information and determined that the totality of the available information does not support issuance of a final rule. Accordingly, the NPRM is withdrawn.

The agency’s own summary, as published.

What this changes

Amends 1 part of the Code of Federal Regulations — the standing rules this notice rewrites.

• 14 CFR 39 Airworthiness Directives