Summary
We propose to adopt a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10- 40, and DC-10-40F airplanes. This proposed AD would require installing a support bracket and coupler on the left and right wing-to-fuselage transition, and metallic overbraid on the left and right leading edge wire assembly. This proposed AD results from fuel system reviews conducted by the manufacturer, as well as reports that the fuel quantity system was affected by lightning-induced transients. We are proposing this AD to prevent lightning-induced transients to the fuel quantity indication system, which could cause voltage levels to go beyond original design levels between fuel tank probes and structure, and become a potential ignition source at the fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.