Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede airworthiness directive (AD) 2008-23-19, Amendment 39-15740 (73 FR 71534, November 25, 2008). That AD applies to the specified products. The NPRM published in the Federal Register on July 23, 2010 (75 FR 43097). That NPRM proposed to continue to require sealing the fasteners on the front and rear spars inside the left and right main fuel tanks and on the rear spar and lower panel of the center fuel tank. That NPRM also proposed to require inspections of the wire bundle support installations to verify if certain clamps are installed and if Teflon sleeving covers the wire bundles inside the left and right equipment cooling system bays, on the left and right rear spars, and on the left and right front spars; corrective actions if necessary; and sealing of additional fasteners on the rear spar inside the left and right main fuel tanks. \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 and the FAA's response to each comment. \n\nConcurrence With the NPRM \n\n\n\tBoeing concurs with the contents of the proposed rule. \n\nRequest To Revise the Compliance Time \n\n\n\tFedEx, US Airways, Delta, European Air Transport Leipzig GmbH (European Air)/DHL Air requested a change in the compliance time. FedEx, Delta, and US Airways requested that we change the compliance time from ''60 months after December 30, 2008,'' to ''60 months after the effective date of the final rule'' in paragraph (h) of the NPRM. European Air/DHL Air requested an extension of the compliance time from 60 months to a minimum of 72 months for airplanes that have already been modified in accordance with Boeing Alert Service Bulletin 757- 57A0064, dated July 16, 2007. FedEx and Delta stated that fuel tank access occurs at 72-month intervals. European Air/DHL Air stated that theypurge the fuel tanks during a 4C-check corresponding to 72 months, 12,000 flight cycles, or 24,000 flight hours, whichever occurs first. European Air/DHL Air stated that the proposed compliance time does not allow a suitable maintenance opportunity to accomplish the additional work without disturbing the scheduled maintenance activities. Delta stated that the proposed compliance time allows approximately 3 years from the effective date of the final rule. Delta considered this requirement an undue burden that is not justified. Delta stated that the SFAR88 initiative and the Aging Aircraft initiatives generally have a timeline of 60 months to upgrade the airplanes based on the FAA harmonization policy of the aging airplane programs per ''Fuel Tank Safety Compliance Extension (Final Rule) and Aging Airplane Program Update (Request for Comments)'' (69 FR 45936, July 30, 2004). \n\tWe agree that the compliance time in paragraph (h) of this AD should be changed to ''within 60 months after the effective date of this AD'' to avoid causing an undue burden on operators who have already accomplished the modification in accordance with Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007. In addition, we consider the following condition may warrant this change in the compliance time. The additional work specified in Boeing Alert Service Bulletin 757-57A0064, Revision 1, dated October 5, 2009, is intended to provide an additional layer of protection to the main fuel tanks to prevent ignition sources from occurring inside those tanks under a lightning strike event. The existing fastener installation is able to tolerate lightning current without introducing ignition sources inside the main fuel tanks if no failure conditions exist. The additional work of sealing the affected fasteners will add a fail-safe design feature to the existing fastener installation so that no ignition sources are introduced under the presence of single failures. Because of this, we consider thatan acceptable level of safety would still be provided with this change in the compliance time. We have also limited the airplanes affected by paragraph (h) of this AD to airplanes on which Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, was done before the effective date of this AD. \n\tWe have also revised paragraph (g) of this AD to add the following sentence: ''As of the effective date of this AD, only Boeing Alert Service Bulletin 757-57A0064, Revision 1, dated October 5, 2009, may be used.'' \n\tWe do not agree with extending the compliance time to 72 months. In developing an appropriate compliance time, we considered the safety implications, parts availability, and normal maintenance schedules for timely replacement of the fasteners. In consideration of all of these factors, we determined that the 60-month compliance time represents an acceptable interval in which the fasteners can be sealed in a timely manner, while still maintaining an acceptable level of safety.According to the provisions of paragraph (j) of this AD, operators may request an alternative method of compliance (AMOC) to request a longer compliance time, if the request is submitted with substantiating data that proves that the longer compliance time will provide an acceptable level of safety. We have not changed the AD further in this regard. \n\nRequest To Allow Modification in Accordance With Original Issue of Service Bulletin \n\n\n\tEuropean Air/DHL Air requested that we allow the modification, in accordance with Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, and Boeing Multi Operator Message (MOM) 1-1046487761, dated November 6, 2008, as an accepted means of compliance. European Air stated that they started incorporating the modifications specified in Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, and Boeing MOM 1-1046487761, dated November 6, 2008, before AD 2008-23-19 was issued. \n\tWe infer that European Air/DHL Air are requesting that weallow the modification done in accordance with Boeing Alert Service Bulletin 757- 57A0064, dated July 16, 2007, and Boeing MOM 1-1046487761, dated November 6, 2008, as a means of compliance with paragraphs (g) and (h) of this AD. We do not agree. Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, is not sufficient to address the unsafe condition, and Boeing MOM 1-1046487761, dated November 6, 2008, merely informs operators of a forthcoming revision to Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, which will include additional work of sealing 40 fasteners that are not identified in Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007. Boeing MOM 1-1046487761, dated November 6, 2008, refers to two sketches that provide the locations of additional \n\n((Page 10228)) \n\nfasteners that must be sealed. Those sketches can help operators to accomplish the additional work, but they only provide figures that are applicable to certain airplane groups identified in Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007. In addition, those sketches are not a published document and cannot be incorporated by reference in the AD. We have determined that it is inappropriate to include Boeing MOM 1-1046487761, dated November 6, 2008, as an accepted means to comply with the actions required by this AD. However, operators who have used those data can still request approval of an AMOC, in accordance with paragraph (j) of this AD. No change has been made to the AD in this regard. \n\nRequest To Clarify Instructions for Continued Airworthiness (ICA) \n\n\n\tContinental stated that proper ICA must be provided in order to prevent inadvertent reversal of implemented changes that can lead to violation of requirements of the SFAR88 program as well as the final rule. Continental Airlines requested that we coordinate with Boeing to ensure proper instructions are provided. \n\tWe acknowledge the commenter's concern. Operators and owners are responsible for ensuring that the configuration mandated by this AD is maintained in accordance with section 39.7 of the Federal Aviation Regulations (14 CFR 39.7). If any new airworthiness limitations (AWLs) related to any of the design features mandated by this AD are developed, we may consider additional rulemaking to mandate incorporation of those AWLs into operators' maintenance programs. The FAA is working with industry to evaluate potential changes to the AD process that are intended to more clearly identify how to maintain configurations that are required for AD compliance. We have not changed the AD regarding this issue. \n\nRequest To Allow Alternative Color of Lacing Tape \n\n\n\tContinental raised a question regarding the color of lacing tape specified in Boeing Alert Service Bulletins 757-57A0064, dated July 16, 2007; and Revision 1, dated October 5, 2009. Continental stated that those service bulletins require use of a lacing tape identified as BMS 13-54, Type III, Class 1, Finish C, Black. Continental stated that a specific color of the lacing tape should not be mandated. Continental stated that Boeing Standard Wiring Process Manual 20-10-11 makes no distinction regarding the color of the lacing tape for sleeve installation. \n\tWe infer that Continental is requesting that we allow any color as long as the lacing tape is BMS 13-54, Type III, Class 1, Finish C. We agree to allow the use of white lacing tape because white is a neutral color that is not associated with any specific color code requirement. However, we disagree with allowing the use of lacing tape with colors other than black or white because use of colors other than black or white may be inconsistent with color-coding used by the manufacturer or operator, and could create confusion in wiring identification. We have granted a global AMOC to allow the use of lacing tape BMS 13-54, Type III, Class 1, Finish C, with white color in place of black color when accomplishing the actions specified in BoeingAlert Service Bulletin 757-57A0064, dated July 16, 2007, as required by paragraph (f) of AD 2008-23-19, Amendment 39-15740. Paragraph (i) has been added to this AD to reflect these changes. \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. We have determined that these 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 the AD. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 667 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per product Cost on U.S. operators -------------------------------------------------------------------------------------------------------------------------------------------------------- Fastener Sealing and Inspections Up to 545 work-hours x $325 Up to $46,650..................... Up to $31,115,550. \n\t(required by AD 2008-23-19). $85 per hour = Up to \n\t$46,325 per airplane \n\tdepending on \n\tconfiguration. Main Tank Fastener Sealing (new Up to 30 work-hours x $0 Up to $2,550...................... Up to $1,700,850. \n\tproposed action). $85 per hour = Up to \n\t$2,550. --------------------------------------------------------------------------------------------------------------------------------------------------------We estimate the following costs to do any necessary replacements that would be required based on the results of the proposed inspection. We have no way of determining the number of aircraft that might need these replacements: \n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per product ---------------------------------------------------------------------------------------------------------------- Clamp Replacement................... Up to 6 work-hours x $0 Up to $510. \n\t$85 per hour = $510. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tAccording to the manufacturer, some 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, \n\n((Page 10229)) \n\npart 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\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.