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 for discrepancies of certain areas of the forward and aft sides of the body station 2598 bulkhead, and repair if necessary. This action is necessary to find and fix such discrepancies of the bulkhead structure, which could result in failure of the structure to carry flight loads of the horizontal stabilizer, and consequent loss of controllability of the airplane. This action is intended to address the identified unsafe condition.