Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 747-8 and 747-8F series airplanes. The NPRM published in the Federal Register on April 5, 2016 (81 FR 19514) (''the NPRM''). The NPRM was prompted by a report that static strength analysis has shown that the aluminum transmission aft bearing plate assemblies have inadequate structural strength for one or more of the required load cases, including cases for drive system jam, flap skew, and structural damage tolerance. Inadequate structural strength can result in damage to the transmission aft bearing plate assemblies. The NPRM proposed to require removing aluminum transmission aft bearing plate assemblies from the flap track and installing titanium transmission aft bearing plate assemblies to the flap track. We are issuing this AD to prevent inadequate structural strength of transmission aft bearingplate assemblies. This condition could result in damaged transmission aft bearing plate assemblies, which could result in incorrect operation and departure of the flap from the airplane and consequent loss of controllability of the airplane. \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 NPRM and the FAA's response to each comment. \n\nRequest To Use the Latest Service Information \n\n\n\tBoeing requested that we revise the NPRM to refer to Boeing Alert Service Bulletin 747-57A2348, Revision 1, dated February 26, 2016. Boeing stated that Boeing Alert Service Bulletin 747-57A2348, dated June 12, 2015, erroneously included three airplanes, line numbers 1435, 1506, and 1509, which were delivered with the terminating action already incorporated. Boeing stated that the airplane effectivity in paragraph 1.A.1. of Boeing Alert Service Bulletin 747-57A2348, Revision 1, dated February 26, 2016, islisted correctly; however, airplane line numbers 1435, 1506, and 1509 were still erroneously included in the table that lists the airplane groups by line numbers. Boeing noted that Boeing Alert Service Bulletin 747-57A2348, Revision 1, dated February 26, 2016, also contains corrections to the access requirements, part quantities, and part numbers. \n\tWe agree with the commenter's request for the reasons provided. We have updated this final rule accordingly. Since the table in paragraph 1.A.1. of Boeing Alert Service Bulletin 747-57A2348, Revision 1, dated February 26, 2016, is not accurate, we have also revised paragraph (c) of this AD to state that the AD is applicable to Model 747-8 and 747-8F series airplanes, except for line numbers 1435, 1506, and 1509, which were delivered with the terminating action already incorporated. We have also added a new paragraph (h) to this AD, which provides credit for actions completed before the effective date of this AD using Boeing Alert Service Bulletin 747-57A2348, dated June 12, 2015. We have redesignated subsequent paragraphs accordingly. \n\nRequest To Revise the Costs of Compliance \n\n\n\tBoeing requested that we update the Costs of Compliance section of the NPRM with the latest information in Boeing Alert Service Bulletin 747-57A2348, Revision 1, dated February 26, 2016. Boeing stated that the work hours and parts costs have been updated with the new service information. \n\tWe agree with the commenter's request for the reason provided. We have updated this final rule accordingly. \n\nRequest for Credit for Previous Actions \n\n\n\tBoeing requested that we add a statement to the NPRM to indicate that no further work is required on airplanes that have completed the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 57A2348, dated June 12, 2015. Boeing stated that Boeing Alert Service Bulletin 747-57A2348, Revision 1, dated February 26, 2016, has no effect on airplanes that have incorporated Boeing Alert Service Bulletin 747-57A2348, dated June 12, 2015. \n\tWe agree with the commenter's request for the reason provided. As stated previously, we have revised this AD to provide credit for actions completed before the effective date of this AD using Boeing Alert Service Bulletin 747-57A2348, dated June 12, 2015. \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 this AD with the changes described previously and minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\tWe also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tWe reviewed Boeing Alert ServiceBulletin 747-57A2348, Revision 1, dated February 26, 2016. The service information describes procedures for removing the aluminum transmission aft bearing plate assembly from the flap \n\n((Page 85120)) \n\ntrack and installing a new titanium transmission aft bearing plate assembly to the flap track. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 11 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators -------------------------------------------------------------------------------------------------------------------------------------------------------- Replacement............................ 136 work-hours x $85 per hour = $11,560........................ $43,787 $55,347 $608,817 -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\n\n\tAccording to the manufacturer, all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate. \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.