Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede airworthiness directive (AD) 89-12-10, which applies to certain The Boeing Company Model 747 series airplanes. AD 89-12-10 currently requires replacement of certain underwing fuel tank access doors with stronger, fire-resistant doors. Since we issued AD 89-12-10, we have received reports indicating that a standard access door was located where an impact-resistant access door was required, and stencils were missing from some impact-resistant access doors. Stencils are required to indicate that the door is impact-resistant and to indicate the correct location for installation of the impact- resistant door. This proposed AD would require an inspection of the left- and right-hand wing fuel tank access doors to determine whether impact-resistant access doors are installed in the correct locations, and replacement of any door with an impact-resistant access door if necessary. This proposed AD would also require an inspection for the presence of stencils and index markers on impact-resistant access doors, and application of new stencils or index markers if necessary. This proposed AD would also require revising the maintenance program to incorporate changes to the airworthiness limitations section. This proposed AD would also add airplanes to the applicability. We are proposing this AD to prevent foreign object penetration of the fuel tank, which could cause a fuel leak near an ignition source (e.g., hot brakes or engine exhaust nozzle), consequently leading to a fuel-fed fire.