Airworthiness Directives; McDonnell Douglas Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain McDonnell Douglas transport category airplanes. This AD requires an initial ultrasonic inspection for cracks of the studbolts of the inboard and outboard hinge fittings of the left and right outboard flaps of the wings. Based on the inspection results, this AD also requires doing repetitive ultrasonic inspections, replacing upper and/or lower studbolts with new or serviceable studbolts, doing a detailed inspection for corrosion of the upper studbolts, doing a magnetic particle inspection for cracks of studbolts, and changing the protection treatment; as applicable. This AD results from reports of corrosion and failures of the upper and lower studbolts of the outboard flaps inboard and outboard hinge fittings. We are issuing this AD to prevent corrosion and subsequent cracking of studbolts, which could result in failure of the flap hinge fittings and their possible separation from the wing rear spar, and consequent reduced controllability of the airplane.