AD 97-07-06 62 FR 16072 Active

This amendment supersedes an existing priority letter airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. Model 412 helicopters, that currently requires a daily inspection of certain swashplate support assemblies. It also requires a reduction in VNE, and installation of appropriate airspeed indicator markings and a placard. This amendment requires the same actions required by the existing priority letter AD, but restricts the applicability to the Model 412 helicopters with a certain steel main rotor control swashplate support assembly (steel swashplate support assembly) installed. This amendment also allows the installation of an improved main rotor control swashplate assembly that terminates the requirements of this AD. This amendment is prompted by reported cracking and in- service failures of certain steel swashplate support assemblies. The actions specified by this AD are intended to prevent failure of the steel swashplate support assembly that could result in loss of main rotor control and subsequent loss of control of the helicopter.