Summary
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 sourcesinside 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.