Federal Aviation Administration August 1, 2007 – Federal Register Recent Federal Regulation Documents

The FAA is revising an earlier proposed airworthiness directive (AD) for all Boeing Model 757 airplanes. The original NPRM would have required revising the Airworthiness Limitations (AWLs) section of the Instructions for Continued Airworthiness by incorporating new limitations for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 requirements. The original NPRM also would have required the initial inspection of certain repetitive inspections specified in the AWLs to phase-in those inspections, and repair if necessary. The original NPRM resulted from a design review of the fuel tank systems. This action revises the original NPRM by aligning the compliance time for revising the AWLs section with the compliance date of the special maintenance program requirements, updating the listing of applicable airplane maintenance manuals in Appendix 1, and clarifying certain actions. We are proposing this supplemental NPRM to prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs, or maintenance actions, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 707 airplanes and Model 720 and 720B series airplanes. This proposed AD would require accomplishing an airplane survey to define the configuration of certain system installations, and repair of any discrepancy found. This proposed AD would also require modifying the fuel system by installing lightning protection for the fuel quantity indication system (FQIS), ground fault relays for the fuel boost pumps, and additional power relays for the center tank fuel pumps and uncommanded on-indication lights at the flight engineer's panel. This proposed AD results from fuel system reviews conducted by the manufacturer. We are proposing this AD to prevent certain failures of the fuel pumps or FQIS, which could result in a potential ignition source inside the fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.