Airworthiness Directives; Agusta Model AB412 Helicopters

This amendment adopts a new airworthiness directive (AD) for Agusta Model AB412 helicopters. This action prohibits use of the hoist until certain modifications are accomplished. This amendment is prompted by the loss of a hoist hook during flight due to an uncommanded firing of the cable cutter cartridge caused by wire chafing. The actions specified in this AD are intended to prevent wire chafing, inadvertent firing of the cable cutter cartridge, loss of a hoist hook and section of cable, impact with the main or tail rotor, and subsequent loss of control of the helicopter.