Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires repetitive inspections to detect cracks in the edge frame web and doubler of the number 1 main entry door cutout; and repair, if necessary. This AD also provides for optional terminating action for the repetitive inspections. This amendment is prompted by reports indicating that fatigue cracks were found in the edge frame web and doubler at the door stop number 1 of the number 1 main entry door cutout. The actions specified by this AD are intended to detect and correct such fatigue cracking, which could result in rapid decompression of the airplane.