Discussion \n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Model 777 airplanes. That NPRM was published in the Federal Register on January 7, 2010 (75 FR 950). That NPRM proposed to require inspecting the bolt, nut, and downstop of the slat track assembly to determine if the bolt, nut, or stops are missing and to determine if the thread protrusion of the bolt from the nut is within specified limits and parts are correctly installed, and related investigative and corrective actions if necessary. For certain airplanes, that NPRM also proposed to require inspecting the slat cans at the outboard slat number 3 and 12 outboard main track locations for holes and wear damage, and corrective actions if necessary; and replacing the downstop hardware for the outboard slats number 3 and 12 outboard and inboard main track locations. \n\nRelevant Service InformationWe have reviewed Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010. The NPRM referred to Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, as the appropriate source of service information. Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010, clarifies procedures, deletes a requirement, adds a note to allow a different fastener, revises an incorrect chamfer callout, and adds information that was published in Boeing Information Notice 777- 57A0064 IN 01 and 777-57A0064 IN 02. Boeing Service Bulletin 777- 57A0064, Revision 1, dated May 6, 2010, does not require additional work. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comments received from the commenters. \n\nSupport for the NPRM \n\n\tContinental Airlines (Continental) supports the intent of the NPRM. \n\nRequest To Add Exception for Group 1 Airplanes \n\n\tBoeing requests that we revise the NPRM to add a statement to paragraph (h) of the NPRM stating, "The outboard main track locations for slats 3 and 12 are excluded from the inspection defined in Table 3 of Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009.'' Boeing states that, for Group 1 airplanes, the slat tracks do not penetrate into the wing fuel tank at these locations. Boeing also states that, for all Group 2 airplanes, this inspection is accomplished via Table 4 of Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009. Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, states that for only Group 2 airplanes the outboard main track locations at slats 3 and 12 must be inspected. Boeing notes that it plans to issue a new revision to this service bulletin in June 2010 that contains this information. \n\tWe disagree with the commenter that such a revision is necessary. We have updated this final rule to refer to Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010. Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010, has corrected this information. We have added Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010, as the appropriate source of service information for the actions required by this AD, including paragraph (g)(2) of this AD (in paragraph (g)(2) of the NPRM we referred to the original issue of the service bulletin for the compliance times but did not specifically reference the service bulletin as the applicable source of service information for doing the actions). We have also added paragraph (j) to this final rule to provide credit for actions done in accordance with Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009. \n\nRequest To Add Exception for Group 2 Airplanes \n\n\tBoeing further requests that we revise paragraph (h) of the NPRM to state, "For airplanes defined as Group 2 in Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, it is not necessary to perform the torque check on the downstop hardware for slats 3 and 12 as defined in Table 2 of Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009.'' Boeing states that at locations where a fastener is to be replaced by subsequent instructions in Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, a torque check is redundant and is not a technical requirement. Boeing states that the visual inspections are still in place to guarantee that damage caused by a loose fastener will be caught. Boeing also adds that Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, specifies compliance times for the fastener replacement that are less than those for the torque check. Boeing notes that it plans to issue a new revision to this service bulletin in June 2010 that contains this information. \n\tWe agree with the commenter that such a revision is necessary. We have updated this final rule to refer to Boeing Service Bulletin 777- 57A0064, Revision 1, dated May 6, 2010. However, we have added a new paragraph (i) to thisfinal rule to clarify that this measurement is not necessary on slats 3 and 12. We have added Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010, as the primary source of service information for accomplishing the actions required by this AD. \n\nRequest To Increase the Inspection Threshold to 12 Months \n\n\tContinental requests that we revise the compliance time for the inspection from 6 months to 12 months after the effective date of the AD. Continental states that the current 6-month compliance time will not provide a practical period in which to complete the full inspection for its Model 777 fleet based on their maintenance schedule. Continental states that a 12-month threshold would not compromise the safety of the airplane because there are existing zonal inspection requirements in the referenced Maintenance Planning Document/ Maintenance Review Board (MPD/MRB) tasks, discrepancies in the area of interest could be detected through the required routine inspections.Continental states that with a frequency of every 1,125 days from delivery, most affected airplanes should have had at least one inspection performed in accordance with the MPD/MRB tasks. \n\tWe disagree. Due to the urgent nature of a potential excessive fuel leakage, we do not find it appropriate to revise the inspection threshold. Furthermore, the MPD/MRB zonal inspection requirements are not intense enough to detect certain unobvious discrepancies (e.g., loose bolts and insufficient nut torque). However, under the provisions of paragraph (k) of this AD, we will consider requests for approval of an extension of the compliance time if sufficient data are submitted to substantiate that the extension would provide an acceptable level of safety. We have not changed the AD in regard to this issue. \n\nRequest To Clarify Requirements of Downstop Fitting Rework \n\n\tEVA Airlines requests that we incorporate the information from Boeing Information Notice 777-57A0064 IN 01, dated May 28, 2009, which states that the chamfer for the -2 stop fitting in view B-B of Appendix A of Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, should be "0.820-0.850 x 90 Degrees-120 Degrees'' instead of "0.820- 0.050 x 90 Degrees-120 Degrees.'' \n\tWe agree that this information should be incorporated into the AD. Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010, corrects this information. As stated previously, we have changed this AD to refer to Boeing Service Bulletin 777-57A0064, Revision 1, dated May 6, 2010, as the primary source of service information for accomplishing the actions required by this AD. \n\nConclusion \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 also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nExplanation of Change to Costs of Compliance \n\n\tSince issuance of the NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate. \n\nCosts of Compliance \n\n\tWe estimate that this AD would affect 129 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tTable--Estimated Costs \n\n\nAction\nWork hours\nAverage labor rate per hour\nParts\nCost per product\nNumber of U.S.-registered airplanes\nFleet cost\nInspection for Group 1 airplanes\n39\n$85\n$0\n$3,315 per inspection cycle\n127\n$421,005 per inspection cycle\nInspection for Group 2 airplanes\n55\n$85\n$0\n$4,675 per inspection cycle\n2\n$9,350 per inspection cycle\nReplacement for Group 2 airplanes\n8\n$85\n$9,267\n$9,947\n2\n$19,894\n\nAuthority for This Rulemaking \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\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), and \n\t(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. \n\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \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, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n 1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The FAA amends Sec. 39.13 by adding the following new AD: