Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This proposal would require repetitive inspections of the aft pressure bulkhead to detect cracking, and repair, if necessary. This proposal is prompted by a report of fatigue cracking found in the upper half of the aft pressure bulkhead. The actions specified by the proposed 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.