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 of the aft pressure bulkhead to detect cracking, and repair, if necessary. This amendment is prompted by a report of fatigue cracking found in the upper half of the aft pressure bulkhead. The actions specified by this AD are intended to detect and correct cracking in the aft pressure bulkhead, which could result in rapid decompression of the fuselage or overpressurization of the tail section.