Airworthiness Directives; The Boeing Company Airplanes
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer. This AD requires installing an automatic shutoff system for the center and auxiliary tank fuel boost pumps, as applicable; installing a placard in the airplane flight deck if necessary; replacing the P5-2 fuel system module assembly; installing the "uncommanded ON" (UCO) protection system for the fuel boost pumps; revising the airplane flight manual (AFM) to advise the flight crew of certain operating restrictions for airplanes equipped with an automatic shutoff system; and revising the maintenance program by incorporating new airworthiness limitations for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 requirements. We are issuing this AD to prevent operation of the center and auxiliary tank fuel boost pumps with continuous low pressure, which could lead to friction sparks or overheating in the fuel pump inlet that could create a potential ignition source inside the center and auxiliary fuel tanks. These conditions, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.