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

概要

This document proposes superseding an existing airworthiness directive (AD) for 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. That AD currently requires updating the product identification, extending the application of the AD to other helicopter models, continuing the existing retirement time for certain main rotor tension- torsion (TT) straps, and adding the TT strap part numbers to the applicability. This action proposes to require removing certain serial- numbered TT straps from service, reduce the retirement life for other TT straps, and establish a retirement life in terms of calendar time in addition to hours time-in-service (TIS) for certain other affected TT straps. This action would also add two model helicopters to the applicability of the AD. This proposal is 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, necessitates a cal