AD FAA-2012-0327

We are superseding an existing airworthiness directive (AD) for certain The Boeing Company 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, and MD-10-30F airplanes. That AD currently requires installing or replacing with improved parts, as applicable, the bonding straps between the metallic frame of the fillet and the wing leading edge ribs, on both the left and right sides of the airplane; and for certain airplanes, repositioning or replacing two bonding straps, doing a bonding-resistance check and an inspection to determine correct installation of certain bonding straps, and applicable corrective actions. This new AD adds airplanes to the applicability and, depending on the airplane configuration, requires installing new braided bonding straps, inspecting to determine if a certain strap is installed and replacing with or installing a braided bonding strap if necessary, measuring the electrical resistance of the bonding straps, verifying that brackets have an acceptable fillet seal, and doing corrective actions if necessary. This AD was prompted by fuel system reviews conducted by the manufacturer, and our determination that additional actions are necessary to address the identified unsafe condition. We are issuing this AD to reduce the potential of ignition sources inside fuel tanks in the event of a severe lightning strike, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.