AD NUMBER: 2005-13-17
MANUFACTURER: Agusta SUBJECT: Airworthiness Directive 2005-13-17 SUMMARY: This amendment adopts a new airworthiness
directive (AD) for the Agusta S.p.A. (Agusta) Model AB412 Series
helicopters. This action requires inspecting each affected tail
rotor blade (blade) forward tip weight retention block (tip block)
and the aft tip closure (tip closure) for adhesive bond voids, and
removing any blade with an excessive void from service.
This AD also requires modifying certain blades by installing
shear pins and tip closure rivets on all affected blades. This
amendment is prompted by reports of in-flight loss of tip blocks
and tip closures resulting in minor to substantial damage. The
actions specified in this AD are intended to prevent loss of the
tip block or tip closure, loss of a blade, and subsequent loss of
control of the helicopter.