Airworthiness Directives; Boeing Model 747 Series Airplanes Powered By Pratt & Whitney JT9D-3 and -7 Series Engines

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires repetitive inspections and torque checks of the hanger fittings and strut forward bulkhead of the forward engine mount and adjacent support structure, and corrective actions, if necessary. The existing AD also provides for optional terminating action for the repetitive inspections and checks. This amendment requires certain new repetitive torque checks and the previously optional terminating action. The actions specified by this AD are intended to prevent loose fasteners and associated damage to the hanger fittings and bulkhead of the forward engine mount, which could result in separation of the engine from the airplane.