Airworthiness Directives; Costruzioni Aeronautiche Giovanni Agusta S.p.A. Model A109A, A109AII, and A109C Helicopters

This amendment adopts a new airworthiness directive (AD), applicable to certain Costruzioni Aeronautiche Giovanni Agusta S.p.A. (Agusta) Model A109A, A109AII, and A109C helicopters, that requires a modification of the tail boom vertical fin to create inspection openings that permit initial and repetitive visual inspections for cracks in the vertical fin rear spar attachment area. This amendment is prompted by four reports of cracks in the tail boom vertical fin rear spar attachment area. The actions specified by this AD are intended to prevent failure of the vertical fin attachment caused by cracks in the tail boom vertical fin rear spar attachment area, and subsequent loss of control of the helicopter.