AD FAA-2008-0978

We are adopting a new airworthiness directive (AD) for certain Model 767-200, -300, and -300F series airplanes. For certain airplanes, this AD requires installing support hardware and modifying the interfacing wiring of the fuel quantity indicating system (FQIS) densitometer. For certain other airplanes, this AD requires replacing the existing hot short protector (HSP) on the FQIS densitometer with a new HSP. This AD also requires revising the Airworthiness Limitations (AWL) section of the Instructions for Continued Airworthiness to incorporate AWL No. 28-AWL-22. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent the center tank fuel densitometer from overheating and becoming a potential ignition source inside the center fuel tank, which, in combination with flammable fuel vapors, could result in a center fuel tank explosion and consequent loss of the airplane.