Airworthiness Directive · Amendment 39-10139 · Boeing Model 747 Series Airplanes
Boeing Model 747 Series Airplanes
Model 747 series airplanes, having line numbers 1 through 500 inclusive, equipped with Pratt & Whitney Model JT9D-3, - 7, or -7Q engines, or having line numbers 202, 204, 232, or 257, equipped with General Electric Model CF6 series engines; certificated in any category; and on which the strut/wing modification has not been accomplished in accordance with either of the following Boeing service bulletins: Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994, or Boeing Alert Service Bulletin 747-54A2158, dated November 30, 1994.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires repetitive inspections to detect cracks, corrosion, or damage of the lower spar fitting body and lug, and corrective actions, if necessary. This AD also provides for optional terminating action for the repetitive inspection requirements. This amendment is prompted by reports that fatigue cracking was found in the lower spar fitting lug on the number 3 pylon and in the lower spar fitting body. The actions specified in this AD are intended to detect and correct such fatigue cracking, which could result in failure of the strut and separation of the engine from the airplane.
