Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires repetitive inspections for cracking of the upper skin of the outboard and center sections of the horizontal stabilizer and the rear spar structure, hinge fittings, terminal fittings, and splice plates; and repair if necessary. This action is necessary to find and fix such cracking, which could lead to reduced structural capability of the outboard and center sections of the horizontal stabilizer, and result in loss of controllability of the airplane. This action is intended to address the identified unsafe condition.