Action
Final rule.
Summary
We are superseding Airworthiness Directive (AD) 2013-23-03, which applies to certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR series airplanes. AD 2013-23-03 required a detailed inspection of certain attach fittings for a cylindrical defect, and replacement if necessary. For certain airplanes, this new AD requires new inspections of the inboard actuator attach fittings for machining defects, and overhaul or replacement if necessary. This new AD also limits the compliance time for doing the replacement for certain other airplanes. This AD was prompted by a report that a machining defect was also found on some of the actuator assemblies inspected during manufacture. This defect could lead to fatigue cracking and subsequent fracture. We are issuing this AD to detect and correct defective inboard actuator attach fittings which, combined with loss of the outboard actuator load path, could result in uncontrolled retraction of the outboard flap, damage to flight control systems, and consequent reduced controllability of the airplane.