A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes was published in the Federal Register on July 16, 1999 (64 FR 38383). That action proposed to require removal of cable guards in the lateral control system and replacement with new, improved cable guards. \n\nComments \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\nSupport for the Proposal \n\n\tOne commenter supports the proposed rule. \n\nRequest to Revise Cost Impact Information \n\n\tOne commenter requests that the cost impact information be revised to include the work hours required to gain access and close up, and to test the lateral flight control system after the replacement of the cable guards. The commenter states that cost impact informationprovided in the proposed rule estimates 10 work hours per airplane is necessary for the replacement, whereas the Boeing service bulletin estimates 31.5 work hours per airplane. \n\n\tThe FAA does not concur with the commenter's request. The cost impact information, below, describes only the "direct" costs of the specific actions required by this AD. The number of work hours necessary to accomplish the required actions, specified as 10 in the cost impact information, below, was provided to the FAA by the manufacturer based on the best data available to date. This number represents the time necessary to perform only the actions actually required by this AD. The FAA recognizes that, in accomplishing the requirements of any AD, operators may incur "incidental" costs in addition to the "direct" costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate. No change to the final rule is necessary in this regard. \n\nRequest to Extend the Compliance Time \n\n\tOne commenter requests that the compliance time for the replacement of the cable guards be extended from 2 years to 4 years. The commenter states that it has replaced deteriorated cable guards found during various inspection and maintenance tasks in the area, but that it is unaware of any cases where deterioration of the cable guards has led to binding of the control cables. Due to the access required for the replacement, the commenter states that a longer compliance time would better accommodate its work schedule. \n\n\tThe FAA does not concur with the commenter's request to extend the compliance time. In developing an appropriate compliance time for this action, the FAA considered the safety implications, parts availability, andnormal maintenance schedules for timely accomplishment of the modification. In consideration of these items, as well as two reports of cable binding due to cable guard deterioration in service, the FAA has determined that 2 years represents an appropriate interval of time allowable wherein the modifications can be accomplished during scheduled maintenance intervals for the majority of affected operators, and an acceptable level of safety can be maintained. No change to the final rule is necessary in this regard. \n\nRequest to Consider Repetitive Inspections in Lieu of Replacement \n\n\tOne commenter requests that the FAA consider allowing repetitive inspections of the cable guards in lieu of the required replacement. The commenter states that repetitive inspections and on-condition replacement of cable guards, as well as the elimination of existing cable guards from spares, provides an acceptable level of safety. The commenter also notes that, on freighters, the lateral control cables are exposed and can be easily inspected. \n\n\tThe FAA does not concur with the commenter's request. The FAA has determined that the eventual replacement of all existing cable guards is required because it is not known how long the cable guards will remain intact after exposure to airplane grease. No change to the final rule is necessary in this regard. \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately 956 Model 747 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 219 airplanes of U.S. registry will be affected by this AD, that it will take approximately 10 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $11,000 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $2,540,400, or $11,600 per airplane. \n\n\tThe cost impact figure discussed above is 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\nRegulatory Impact \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." \n\nList 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\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13is amended by adding the following new airworthiness directive: