Airworthiness Directives; Boeing Model 747-100, -200, -300, 747SR, and 747SP Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747-100, -200, -300, 747SR, and 747SP series airplanes, that currently requires a one-time inspection to detect cracking of the longeron splice fittings at stringer 11, on the left and right sides at body station 2598, and replacement of any cracked fitting with a new fitting. This amendment reduces the compliance time for accomplishment of the currently required inspection and adds a new requirement for repetitive inspections. This amendment is prompted by reports that fatigue cracking was found on longeron splice fittings. The actions specified by this AD are intended to detect and correct such fatigue cracking, which could result in reduced controllability of the horizontal stabilizer.