Airworthiness Directives; Eurocopter France Model SA.315B, SA.316B, SA.316C, SA.319B, and SE.3160 Helicopters

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-04-40 which was sent previously to all known U.S. owners and operators of Eurocopter France Model SA.315B, SA.316B, SA.316C, SA.319B, and SE.3160 helicopters by individual letters. This AD requires, for certain blades, inspecting each blade spar for cracks using a dye-penetrant inspection, and visually inspecting each blade cuff for cracks. If a crack is discovered in either a blade spar or cuff, removal and replacement of the blade with an airworthy blade is required prior to further flight. This amendment is prompted by an accident in which a Model SA.315B helicopter lost a main rotor blade (blade) just prior to take-off. The cause of the blade failure was determined to be fatigue cracks that originated from the outboard blade-to-cuff attachment bolt hole and progressed through the blade spar and cuff. This condition, if not corrected, could result in separation of a blade and subsequent loss of control of the helicopter.