Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM published in the Federal Register on December 19, 2011 (76 FR 78574). That NPRM proposed to require repetitive high frequency eddy current (HFEC) inspections of the underwing longeron fitting for cracking, and related investigative and corrective actions if necessary. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal (76 FR 78574, December 19, 2011), and the FAA's response to each comment. \n\nRequest To Use Revised Service Information \n\n\n\tBoeing, UPS, and United Airlines (United) requested that the NPRM (76 FR 78574, December 19, 2011) use the revised service information, which is Boeing Alert Service Bulletin 767-57A0126, Revision 2, dated March 12, 2012. (The NPRM referred to Boeing AlertService Bulletin 767-57A0126, dated August 12, 2011, as revised by Boeing Service Bulletin 767-57A0126, Revision 1, dated November 9, 2011, as the appropriate source of service information for accomplishing the proposed requirements.) Boeing stated that the correction of the airplane variable effectivity table does not change the intent of the NPRM, because applicability paragraph (c) of the NPRM states that ''This AD applies to all The Boeing Company Model 767-200, -300, -300F and -400ER series airplanes; certified in any category.'' Boeing also stated that including Boeing Alert Service Bulletin 767-57A0126, Revision 2, dated March 12, 2012, in the AD might prevent confusion for operators of these airplanes. \n\tWe agree with this request because Boeing Alert Service Bulletin 767-57A0126, Revision 2, dated March 12, 2012, clarifies inspection areas and \n\n((Page 46933)) \n\ncorrects various typographical errors. Since the NPRM (76 FR 78574, December 19, 2011) applied to all Model 767-200, -300, -300F and -400ER series airplanes, the corrected effectivity in Boeing Alert Service Bulletin 767-57A0126, Revision 2, dated March 12, 2012, does not affect the applicability of this AD. We have changed the final rule to reference Boeing Alert Service Bulletin 767-57A0126, Revision 2, dated March 12, 2012. We have also added new paragraph (i) to the final rule to give credit for actions accomplished before the effective date of this AD using Boeing Alert Service Bulletin 767-57A0126, dated August 12, 2011, as revised by Boeing Service Bulletin 767-57A0126, Revision 1, dated November 9, 2011, and re-identified subsequent paragraphs accordingly. \n\nRequest To Address Effects of NPRM (76 FR 78574, December 19, 2011) on Winglets \n\n\n\tAviation Partners Boeing (APB) commented that it has reviewed the NPRM (76 FR 78574, December 19, 2011), and Boeing Alert Service Bulletin 767-57A0126, dated August 12, 2011, and has determined that the installation of winglets, per Supplemental Type Certificate (STC) ST01920SE, ''does not affect them.'' We infer that APB means the installation of these winglets does not affect accomplishing the NPRM. \n\tAmerican Airlines (American) stated that the NPRM (76 FR 78574, December 19, 2011) does not refer to any effects this inspection or potential repair would have on aircraft equipped with APB winglets. American stated that the NPRM should include a reference to procedures or subsequent actions which may need to be taken over and above the repair, if a repair was to be installed on an airplane with such winglets. \n\tWe agree that the AD should clarify procedures to address these APB winglets. We have added new Note 1 to paragraph (c) of this AD to state that installation of STC ST01920SE (http://rgl.faa.gov/Regulatory-and- Guidance-Library/rgstc.nsf/0/082838ee177dbf62862576a4005cdfc0/$FILE/ ST01920SE.pdf) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01920SE is installed, a ''change in product'' AMOC approval request is not necessary to comply with the requirements of 14 CFR 39.17. For all other AMOC requests, the operator must request approval according to paragraph (j) of this AD. \n\nRequest To Increase Compliance Times \n\n\n\tUnited suggested the initial inspection compliance time of within 3,000 flight cycles or 7,000 flight hours, whichever occurs first, for airplanes that have accumulated over 70,000 total flight hours but less than 20,000 total flight cycles, be to changed to within 6,000 flight cycles or 14,000 flight hours, whichever occurs first. United also stated that, as an alternative for any airplane with less than 20,000 total flight cycles and less than 90,000 total flight hours, the initial inspection threshold of ''within 3,000 flight cycles'' be imposed. United stated that imposing the 3,000-flight-cycle or 7,000- flight-hour compliance times, whichever occurs first, might be more suitable for those airplanes with veryhigh flight cycles, such as over 30,000 or 35,000 total flight cycles. \n\tUnited stated it has reviewed its maintenance history and the most recent inspection results of maintenance planning data (MPD) structural tasks (53-622-00 and 53-632-00) on four of its high-time airplanes. United stated it had no findings, and based on its maintenance history, it considers the initial inspection threshold of 7,000 flight hours or 3,000 flight cycles, whichever occurs first, on any airplane with more than 70,000 total flight hours to be overly aggressive for those operators, like United, that fly airplanes on long routes with very few flight cycles. With average flight hours of approximately 4,500 and approximately 650 flight cycles per year, United stated that the 7,000- flight-hour initial inspection threshold will provide only an approximate 18-month window of opportunity to accomplish the initial inspection on many of its airplanes. United asserts that the 18-month threshold does not provideenough time to schedule this inspection on this many airplanes at a heavy maintenance environment, which is when it should be accomplished. \n\tWe do not agree, because fatigue analysis is based on statistical methods. Statistics from four airplanes using only the MPD general visual inspections, without the benefit of an HFEC inspection, does not provide sufficient statistical justification to increase the compliance time. In developing an appropriate compliance time for this AD, we considered the unsafe condition as well as the recommendations of the manufacturer, and the practical aspect of accomplishing the required inspection within an interval of time that corresponds to the normal maintenance schedules of most affected operators. We have not changed the final rule in this regard. \n\nRequest To Revise On-Condition Costs \n\n\n\tUPS stated that the estimated on-conditions parts cost specified in the NPRM (76 FR 78574, December 19, 2011) only reflect the cost for one wing. \n\tWe agree. We have confirmed that one top-kit is required for each wing, and that the parts costs for both wings ranges up to $14,290. We have revised the estimated on-condition costs in the final rule to include the cost required for both wings. \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these minor changes: \n\t(Agr)re consistent with the intent that was proposed in the NPRM (76 FR 78574, December 19, 2011) for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM (76 FR 78574, December 19, 2011). \n\tWe also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nInterim Action \n\n\n\tWe consider this AD interim action. The design approval holderis currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we might consider additional rulemaking. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 417 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Repetitive HFEC inspection....... 3 work-hours x $85 $0 $255 per inspection $106,335 per \n\tper hour = $255 cycle. inspection cycle. \n\tper inspection \n\tcycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\n((Page 46934)) \n\n\n\tWe estimate the following costs to do any necessary inspections and replacements that would be required based on the results of the inspection. We have no way of determining the number of aircraft that might need these on-condition actions. \n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per product ---------------------------------------------------------------------------------------------------------------- Tension bolt hole and front 104 work-hours x Up to $14,290................ Up to $23,130. \n\tspar lower chord HFEC $85 per hour = \n\tinspection and fitting $8,840. \n\treplacement. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWehave received no definitive data that would enable us to provide cost estimates for cracking repairs specified in this AD. \n\nAuthority for this Rulemaking \n\n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: ''General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) 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. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.