Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 777 airplanes. This proposed AD was prompted by an evaluation by the design approval holder (DAH) indicating that the lap splices of the aft pressure bulkhead webs are subject to widespread fatigue damage (WFD). This proposed AD would require repetitive inspections for any crack in the aft webs of the radial lap splices of the aft pressure bulkhead, and, if necessary, corrective actions. We are proposing this AD to detect and correct fatigue cracking in the aft webs of the radial lap splices of the aft pressure bulkhead, which could result in reduced structural integrity of the airplane and decompression of the cabin.