Airworthiness Directives; Bell Helicopter Textron Canada Limited Model 206L, L-1, L-3, and L-4 Helicopters

This amendment supersedes an existing airworthiness directive (AD) for the specified Bell Helicopter Textron Canada Limited (BHTCL) model helicopters that currently requires removing the horizontal stabilizer supports and inspecting the edges of the tailboom skins around the horizontal stabilizer openings for a crack. This amendment requires checking and inspecting the tailboom for a crack and modifying or replacing the tailboom as necessary. This amendment also provides a terminating action, incorporates a more recent alert service bulletin (ASB), and increases the compliance time for performing the inspections. This amendment is prompted by several reports of cracks found during mandatory inspections. The actions specified by this AD are intended to detect a crack in the tailboom skin and to prevent separation of the tailboom and subsequent loss of control of the helicopter.