Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 757-200, -200CB, -200PF, and -300 series airplanes. This proposed AD would require installation of an automatic shutoff system for the center tank fuel boost pumps, and installation of a placard in the airplane flight deck if necessary. This proposed AD would also require revisions to the Limitations and Normal Procedures sections of the airplane flight manual to advise the flightcrew of certain operating restrictions for airplanes equipped with an automated center tank fuel pump shutoff control. This proposed AD would also require a revision to the Airworthiness Limitations (AWLs) section of the Instructions for Continued Airworthiness to incorporate AWL No. 28- AWL-20 and No. 28-AWL-26. This proposed AD would also require replacement of the fuel control panel assembly with a modified part, installation of two secondary pump control relays for the center tank fuel pumps, other specified actions,and concurrent modification of the fuel control panel assembly. This proposed AD results from fuel system reviews conducted by the manufacturer. We are proposing this AD to prevent center tank fuel pump operation with continuous low pressure, which could lead to friction sparks or overheating in the fuel pump inlet or could create a potential ignition source inside the center fuel tank; these conditions, in combination with flammable fuel vapors, could result in a center fuel tank explosion and consequent loss of the airplane.