Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2014-03-07, Amendment 39-17744 (79 FR 9392, February 19, 2014) (''AD 2014-03-07''). AD 2014-03-07 applied to certain The Boeing Company Model MD-11 and MD-11F airplanes. The NPRM published in the Federal Register on August 17, 2017 (82 FR 39062). The NPRM was prompted by the determination that it is necessary to require an inspection of the wire bundles for damage at certain center upper auxiliary fuel tank locations on certain airplanes. The NPRM proposed to continue to require inspecting certain locations of the wire bundles of the center upper auxiliary fuel tank for damage, and corrective action if necessary. The NPRM also proposed to continue to require installing nonmetallic barrier/shield sleeving, new clamps, new attaching hardware, and a new extruded channel. The NPRM proposed to add certain inspections and expand the applicability. We are issuing this AD to reduce the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane. \n\n((Page 16195)) \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\nSupportive Comments \n\n\n\tThe Air Line Pilots Association, International and Boeing supported the content of the NPRM. \n\nRequest To Clarify NPRM Requirements \n\n\n\tFedEx Express (FedEx) asked that the requirements in the NPRM relative to the referenced service information be clarified. FedEx stated that Boeing Service Bulletin MD11-28-126 has been revised 6 times, and its related AD has been superseded twice; therefore, the NPRM requirements are confusing. FedEx added that the NPRM might need to be re-written completely to clearly state what the new requirements are, since some operators have accomplished either the original issue or one or more of Revisions 1 through 5 of Boeing Service Bulletin MD11-28-126. FedEx stated that it has accomplished Boeing Service Bulletin MD11-28-126, Revision 4, dated November 29, 2011; and at the time those procedures were done, the FedEx fleet was classified as Group 1, Configuration 1, and Group 2, Configuration 1 airplanes because FedEx didn't accomplish prior revisions of the service information. FedEx noted that currently its airplanes are Group 1, Configuration 2, and Group 2, Configuration 2, because FedEx has accomplished prior revisions of Boeing Service Bulletin MD11-28-126 on its airplanes. \n\tWe acknowledge the commenter's request and agree to clarify. The new requirements of this AD apply only to certain airplanes identified in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. As noted by the commenter, for a given airplane, the group and configuration might have changed between Boeing Service Bulletin MD11- 28-126, Revision 4, dated November 29, 2011, and Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. \n\tGroup 1, Configuration 1 airplanes in Boeing Service Bulletin MD11- 28-126, Revision 4, dated November 29, 2011, are defined as airplanes on which ''prior issues of this service bulletin'' have not been accomplished. If the actions specified in Boeing Service Bulletin MD11- 28-126, Revision 4, dated November 29, 2011, have been done on one of these airplanes, this airplane becomes a Group 1 Configuration 2 airplane as defined in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, (airplanes on which ''prior issues of this service bulletin'' have been accomplished). Therefore, for this airplane, the inspections specified in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, for its new configuration must be done. \n\tThe inspections in paragraph (i) of this AD must be done for airplanes identified as Groups 1, 2, and 5, Configuration 2 airplanes in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. For this configuration, Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, adds certain work instructions that were not in Boeing Service Bulletin MD11-28-126, Revision 4, dated November 29, 2011; or Boeing Service Bulletin MD11-28-126, Revision 5, dated July 29, 2014. Therefore, we have not changed this AD in this regard. \n\nRequest To Clarify New Inspection Requirements \n\n\n\tFedEx asked that the new inspection requirements specified in the proposed AD be clarified. FedEx stated that the proposed AD would retain all requirements of AD 2014-03-07, and would add inspection requirements for certain airplanes, as well as expanding the applicability. FedEx noted that Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, adds new inspection requirements but does not specify that the inspection be done at additional locations, as indicated in the proposedAD. FedEx added that the work instructions specified in Revisions 4 and 6 of Boeing Service Bulletin MD11-28-126 are for the same area, so it is not clear which additional locations are mandated by the proposed AD. \n\tWe agree to clarify. Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, adds an inspection to determine if the wire bundles routed above the center upper auxiliary fuel tank between floor beams touch the upper surface of the tank for Groups 1, 2, and 5, Configuration 2 airplanes. We acknowledge that the phrase ''additional locations'' is unclear, and we have revised paragraph (i)(1) of this AD to state ''Do a general visual inspection of the wire bundles at the applicable center upper auxiliary fuel tank locations . . .'' Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, identifies the applicable inspection areas. \n\nRequest To Specify Airplane Configuration \n\n\n\tFedEx asked that the airplane configurations specified in the proposed AD be clarified. FedEx stated that paragraph (i) of the proposed AD specifies the following: ''For Groups 1, 2, and 5 Configuration 2 airplanes, as identified in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016.'' FedEx added that, as defined in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, the FedEx fleet will be Group 1, Configuration 2 and Group 2, Configuration 2 airplanes because FedEx has accomplished a prior revision of this service information. FedEx believes its fleet should be in Group 1, Configuration 1, and Group 2, Configuration 1, but stated that it is not clear which airplanes are in which groups and configurations. \n\tWe acknowledge the commenter's request and provide the following clarification. Paragraph 1.A., ''Effectivity'' of Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, specifies that airplanes on which previous issues of the service information have been done are identified as Configuration 2 airplanes. Therefore, any airplanes on which any previous issue of the service information was accomplished would be classified as Configuration 2. We have not changed this AD in this regard. \n\nRequest for Credit for Previous Actions Accomplished \n\n\n\tFedEx and United Parcel Service (UPS) requested credit for previous accomplishment of the actions in paragraphs (i)(1) and (i)(2) of the proposed AD using Boeing Service Bulletin MD11-28-126, Revision 4, dated November 29, 2011. \n\tFedEx stated that new inspections and corrective actions as specified in paragraphs (i)(1) and (i)(2) of the proposed AD were already performed by FedEx per Boeing Service Bulletin MD11-28-126, Revision 4, dated November 29, 2011, and should not be performed again. FedEx believes the proposed AD should give credit for work accomplished under Boeing Service Bulletin MD11-28-126, Revision 4, dated November 29, 2011. \n\tUPS stated that prior accomplishment of Boeing Service Bulletin MD11-28-126, Revision 4, datedNovember 29, 2011, for Groups 1 and 2, Configuration 1 freighter aircraft meets the requirements of Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. UPS stated that the additional steps added by Revisions 5 and 6 of \n\n((Page 16196)) \n\nBoeing Service Bulletin MD11-28-126 are not applicable to airplanes in freighter configurations or have already been accomplished using Boeing Service Bulletin MD11-28-126, Revision 4, dated November 29, 2011. UPS added that no further actions should be required on those airplanes. \n\tWe agree to clarify. As stated previously, Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, adds an inspection to determine if the wire bundles routed above the center upper auxiliary fuel tank between floor beams touch the upper surface of the tank for Groups 1, 2, and 5, Configuration 2 airplanes. This inspection was not included in Boeing Service Bulletin MD11-28-126, Revision 5, dated July 29, 2014; nor any of the previous revisions of Boeing Service Bulletin MD11-28-126. In addition, for compliance with this AD, this inspection must be done before the detailed inspection specified in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, for Groups 1, 2, and 5, Configuration 2 airplanes. However, under the provisions of paragraph (m) of this AD, we will consider requests for approval of alternative methods of compliance (AMOCs) if sufficient data are submitted to substantiate that the actions would provide an acceptable level of safety. We have not changed this AD in this regard. \n\tWe also partially agree with the commenter. The new requirements in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016, do not apply to certain freighter airplanes. Freighter airplanes are included in the procedures for Groups 1 and 5, Configuration 2 airplanes, but not for Group 2, Configuration 2 airplanes, as specified in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. Onlypassenger airplanes are included in the procedures for Group 2, Configuration 2 airplanes in Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. Therefore, we have added ''as applicable'' to the introductory text to paragraph (i) of this AD to clarify that the actions in paragraphs (i)(1) and (i)(2) of this AD apply to Groups 1 and 5, Configuration 2 airplanes, and passenger airplanes in Group 2, Configuration 2. \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 as proposed, except for minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tWe reviewed Boeing Service Bulletin MD11-28-126, Revision 6, dated July 1, 2016. This service information describes procedures for inspecting certain wire bundles of the center auxiliary fuel tank for damage, and repairing or replacing damaged wires. This service information also describes procedures for installing barrier/shield sleeving, clamping, and an extruded channel. 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 125 airplanes of U.S. registry. We 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 -------------------------------------------------------------------------------------------------------------------------------------------------------- Inspection/installation (retained 168 to 182 work-hours x $85 $15,708 to $28,005...................... $29,988 to $3,748,500 to \n\tactions from AD 2009-26-16, per hour = $14,280 to $43,475 per $5,434,375 per \n\tAmendment 39-16155 (74 FR 69249, $15,470 per inspection inspection cycle. inspection cycle. \n\tDecember 31, 2009)). cycle. Inspection/installation for Groups Up to 9 work-hours x $85 $6,166.................................. Up to $6,931......... Up to $866,375. \n\t1, 2, and 5, all Configuration 2 per hour = $765. \n\tairplanes (retained actions from \n\tAD 2014-03-07). Inspection/installation for Groups Up to 4 work-hours x $85 $0...................................... Up to $340........... Up to $42,500. \n\t1, 2, and 5, all Configuration 2 per hour = $340. \n\tairplanes (new action). Inspection/installation for Line 4 work-hours x $85 per hour $28,005................................. $340................. $28,345. \n\tNumber 579 (new action). = $340. -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that enables us to provide cost estimates for the on-condition actions 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\tThis AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes and associated appliances to the Director of the System Oversight Division. \n\n((Page 16197)) \n\nRegulatoryFindings \n\n\n\tWe have determined that this 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.