Airworthiness Directive · Amendment 39-13550 · Boeing Model 707 and 720 Series Airplanes
Boeing Model 707 and 720 Series Airplanes
Model 707 and 720 series airplanes, as listed in Boeing 707 Alert Service Bulletin A3509, dated June 13, 2002; certificated in any category.
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 707 and 720 series airplanes, that requires repetitive inspections of the upper and lower barrel nuts and bolts that retain the aft trunnion support fitting of each main landing gear for corrosion, cracks, and loose or missing nuts and bolts; torque checks of the upper and lower bolts to verify the torque is within a specified range; and corrective actions, if necessary. This action is necessary to detect and correct cracking and/or loss of the barrel nuts and bolts that retain the aft trunnion support fitting, which could result in the collapse of the main landing gear upon landing. This action is intended to address the identified unsafe condition.
