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 all Boeing Model 767-400ER series airplanes was published in the Federal Register on October 1, 2003 (68 FR 56598). That action proposed to require repetitive high frequency eddy current inspections of the aft lower lugs of the deflection control track of the outboard flap for cracks, and replacement of any cracked deflection control track with a new track assembly. \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\nRequest To Change Compliance Time \n\n\tOne commenter requests that the proposed repairs be deferred until the next major base visit. The commenter states that the compliance time of ''before the accumulation of 12,000 total flight cycles'' in the proposed AD would cause maintenance program issues. The commenter states that the inspections and repairs will create an undue burden to the airline operators due to parts availability and the costs affiliated with immediate repair of a cracked deflection control track. \n\n\tThe FAA does not agree with the commenter's request to change the compliance time. In developing an appropriate compliance time for this action, we considered the safety implications, parts availability, and normal maintenance schedules for the timely accomplishment of the inspections and repairs. We have determined, based on fatigue analysis by the manufacturer, that a compliance time of ''before the accumulation of 12,000 total flight cycles'' will ensure an acceptable level of safety. We also provided a grace period of 1,200 flight cycles, in order to allow the operators to align the inspections with regular maintenance checks. Last, due to safety implications and the consequences associated with continued service without proper repair, repairs must be made before further flight. \n\nModel 767-400ER Not Subject to Proposed AD \n\n\tThe commenter states that all of the cracked deflection control tracks were reported on Model 767-300 series airplanes and no reports have been made for Model 767-400ER series airplanes. The commenter also states that the utilization for the Model 767-300 series airplanes and Model 767-400ER series airplanes are often completely different. \n\n\tWe infer from the commenter's statement, that the Model 767-400ER deflection control tracks should not be subject to the proposed AD. While we do agree that the airplanes operate differently and cracking has only been found on Model 767-300 series airplanes, we do not agree with the commenter that Model 767-400ER deflection control tracks should not be subject to this AD. Based on fatigue analysis and similar construction, we find sufficient data exists to establish the probability of the deflection control track cracking on the Model 767- 400ER series airplanes. Since the deflection control track acts as a secondary load path on Model 767-400ER series airplanes and not on Model 767-300 series airplanes, this AD is limited to Model 767-400ER series airplanes only. \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 38 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 3 work hours per airplane to accomplish the required inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $7,410, or $195 per airplane, per inspection cycle. \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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.\n \n\tFor the reasons discussed above, I certify that this action (1) is not a ''significant regulatory action'' under ExecutiveOrder 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\nAccordingly, 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\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113,44701. \n\n§ 39.13 (Amended) \n\n2. Section 39.13 is amended by adding the following new airworthiness directive: