Airworthiness Directives; Boeing Model 747 Series Airplanes Equipped With General Electric CF6-80C2 Engines

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires modification of the fire extinguishing system in the number two engine strut. This amendment is prompted by reports of chafing of the fire extinguishing tubes [[Page 8539]] in a certain inboard strut to wing area. The actions specified by this AD are intended to prevent chafing of the fire extinguishing tube; such chafing could cause cracking of the tube and consequently produce a hole in the fire extinguishing tube, which could prevent the proper distribution of the fire extinguisher agent within the nacelle in the event of a fire.