Airworthiness Directives; Agusta S.p.A. Model A109A and A109A II Helicopters

This amendment supersedes an existing airworthiness directive (AD), applicable to Agusta Model A109A and A109A II helicopters, that currently requires inspecting each tail rotor blade (blade) for a crack and replacing any cracked blade. This amendment requires, before further flight, inspecting any blade with 400 or more hours time-in- service (TIS) for a crack and replacing any cracked blade. This amendment is prompted by another report of a cracked blade since the issuance of the existing AD. Two of the three occurrences of cracked blades involved the loss of the tail rotor and 90-degree gearbox. The actions specified by this AD are intended to prevent fatigue failure of the blade, loss of the tail rotor, and subsequent loss of control of the helicopter.