Airworthiness Directive · Amendment 39-11105 · Boeing Model 747 Series Airplanes
Boeing Model 747 Series Airplanes
Model 747 series airplanes, line positions 1 through 886 inclusive; equipped with Pratt & Whitney JT9D-3 or -7, or General Electric CF6-45 or -50 engine struts; certificated in any category.
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires repetitive detailed visual inspections for corrosion, and repetitive high frequency eddy current (HFEC) inspections for cracks, of the upper link assembly on the number 2 and number 3 engine struts, and corrective actions, if necessary. This amendment is prompted by reports of corrosion and cracks located at the four fasteners that attach to the aft end to the upper link assembly on the number 2 and number 3 engine struts. The actions specified by this AD are intended to prevent failure of the upper link due to cracking or corrosion, subsequent damage to other strut support structure, and in-flight separation of an engine from the airplane.
