Airworthiness Directives; Boeing Model 757 Airplanes

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 757 series airplanes. That AD currently requires revising the Airworthiness Limitations section of the maintenance manual (757 Airworthiness Limitations Instructions (ALI)) to incorporate certain inspections and compliance times to detect fatigue cracking of principal structural elements (PSEs). This new AD requires incorporating a new revision to the Airworthiness Limitations section of the Instructions of Continued Airworthiness to mandate certain repetitive inspections for fatigue cracking of PSEs, and adds airplanes to the applicability in the existing AD. This AD results from a new revision to the ALI. We are issuing this AD to ensure that fatigue cracking of various PSEs is detected and corrected; such fatigue cracking could adversely affect the structural integrity of these airplanes.