Airworthiness Directives; Bell Helicopter Textron Canada Model 206L, 206L-1, and 206L-3 Helicopters

This amendment revises an existing airworthiness directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 206L, 206L-1, and 206L-3 helicopters with a certain part numbered tailboom installed, that currently requires a visual inspection of the tailboom skin in the areas around the nutplates and in the areas of the tailboom drive shaft cover retention clips for cracks and corrosion using a 10-power or higher magnifying glass until the tailboom is replaced with an airworthy tailboom. This action requires the same actions as the existing AD, but allows a longer interval for the repetitive inspections if the tailboom is modified to increase its structural integrity. Replacement with an airworthy tailboom other than a part- numbered tailboom affected by this amendment constitutes a terminating action for the requirements of this AD. This amendment is prompted by an accident and several reports of fatigue cracks in the tailboom skin in the areas around the nutplates for the tail rotor fairing and in the areas of the tail rotor drive shaft cover retention clips. The actions required by this AD are intended to prevent failure of the tailboom and subsequent loss of control of the helicopter.