Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires a one-time inspection to identify all alloy steel bolts on the body station 1480 bulkhead splice, and corrective action if necessary; and provides for optional terminating action for certain requirements of that AD. This amendment requires accomplishment of the previously optional terminating action. The actions specified by this AD are intended to prevent cracked or broken bolts, which could result in structural damage and rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.