Summary
We are revising an earlier proposed airworthiness directive (AD) for certain 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, and MD-10-30F airplanes. That action (the first supplemental NPRM) would have superseded an existing AD that currently requires installing or replacing with improved parts, as applicable, the bonding straps between the metallic frame of the fillet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. The first supplemental NPRM proposed to add a requirement to reposition or replace two bonding straps for certain airplanes. This action resulted from fuel system reviews conducted by the manufacturer. This second supplemental NPRM would add, for certain airplanes, a bonding- resistance check and an inspection to determine correct installation of certain bonding straps, and applicable corrective actions. We are proposing this second supplemental NPRMto 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.