A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 89-14-04, amendment 39-6246 (54 FR 27157, June 28, 1989), which is applicable to certain Boeing Model 747-400 series airplanes, was published in the Federal Register on September 7, 1995 (60 FR 46542). The action proposed to supersede AD 89-14-04 to require replacement of the wire and sleeve with a single wire in two non-metallic sleeves in the conduit in the struts of each engine. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\n\tOne commenter supports the proposed rule. \n\n\tSeveral commenters request that the compliance time for accomplishment of the replacement be extended from the proposed 12 months. Two of these commenters request an extension that will allow the replacement to be accomplished during a regularly scheduled "C" check(15 to 18 months), when the airplanes will be brought to a main base for an extended hold. These two commenters state that, in order to accomplish the replacement with the proposed compliance time, they would have to special schedule their fleet of airplanes, which would entail considerable additional expense. Another commenter states that it is currently accomplishing the modification required by AD 95-13-05, amendment 39-9285 (60 FR 33333, June 28, 1995), which includes a wiring modification that is equivalent to that proposed in the notice. This commenter further states that it will complete that modification in approximately four years; therefore, compliance with the proposed wiring replacement should be extended accordingly. \n\n\tThe FAA does not concur. In developing an appropriate time for this action, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the availability of required parts and the practical aspects ofaccomplishing the required replacement during affected operators' scheduled maintenance visits. In addition, the FAA has received reports that the wire chafing condition led to short circuits on airplanes that had accumulated 12,000 to 18,310 total flight hours after the incorporation of the modification required by AD 89-14-04. In light of this, the FAA has determined that the accumulated flight hours of some of the affected airplanes may be close to this range at the end of the 12 month compliance time. The FAA has also determined that a compliance time of 4 years for incorporation of the modification, as required by AD 95-13-05, is unacceptable. Such a compliance time would not address the subject unsafe condition in a timely manner. However, under the provisions of paragraph (b) of the final rule, the FAA may approve request for adjustments to the compliance time if data are presented to justify such an adjustment. \n\n\tAfter careful review of the available data, including thecomments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\n\tThere are approximately 311 Model 747-400 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 38 airplanes of U.S. registry will be affected by this AD, that it will take approximately 80 work hours per airplane to accomplish the required action, and that the average labor rate of $60 per work hour. Required parts will cost approximately $673 per airplane. Based on these figures, the cost impact on U.S. operators of the new requirements of this AD is estimated to be $207,974, or $5,473 per airplane. \n\n\tThe cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. \n\n\tThe regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."List of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 USC 106(g), 40113, 44701. § 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by removing amendment 39-6246 (54 FR 27157, June 28, 1989), and by adding a new airworthiness directive (AD), amendment 39-9511, to read as follows: