Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment supersedes two existing airworthiness directives (ADs), applicable to all Boeing Model 747 series airplanes, that currently require that the FAA-approved maintenance inspection program be revised to include inspections that will give no less than the required damage tolerance rating for each structural significant item, and repair of cracked structure. Those ADs were prompted by a structural re-evaluation that identified additional structural elements where, if damage were to occur, supplemental inspections may be required for timely detection of fatigue cracking. This amendment requires additional and expanded inspections, and repair of cracked structure. This action also expands the applicability of the existing ADs to include additional airplanes. The actions specified by this AD are intended to ensure the continued structural integrity of the entire fleet of Model 747 series airplanes. This action is intended to address the identified unsafe condition.