Airworthiness Directives; Arrow Falcon Exporters, Inc. (Previously Utah State University), et al., 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 UH-1B (SW204 and SW204HP) and UH-1H (SW205) Helicopters

Résumé

This document proposes adopting a new airworthiness directive (AD) for the specified type-certificated military surplus helicopters. The AD would require: Creating a component history card or equivalent record for each main rotor grip (grip); determining and recording the total hours time-in-service (TIS) for each grip; visually inspecting the upper and lower tangs of the grip for a crack; inspecting the grip buffer pads for delamination and if delamination is present, inspecting the grip surface for corrosion or other damage; inspecting the grip for a crack using ultrasonic (UT) and fluorescent-penetrant inspection methods; and establishing a retirement life for certain grips. This proposal is prompted by three in-flight failures of grips installed on Bell Helicopter Textron, Inc. (BHTI) Model 212 helicopters, which resulted from cracks originating in the lower main rotor blade bolt lug. The actions specified by the proposed AD are intended to prevent failure of the grip, separation of a main rotor blade, and subsequent loss of control of the helicopter.