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 787-8 airplanes. The NPRM published in the Federal Register on May 11, 2016 (81 FR 29206) (''the NPRM''). The NPRM was prompted by reports indicating that certain wing side-of-body upper stringer fittings have been installed with faying surface mismatch beyond the allowed machining tolerance. The NPRM proposed to require inspection of certain stringer fittings for faying surface mismatch common to the side-of-body rib chord, replacement if necessary, and replacement of the clearance fit fasteners common to the side-of-body fittings and upper side-of-body rib chord with tapered sleeve bolts. We are issuing this AD to prevent an unacceptable reduction of the fatigue life in the upper side-of-body rib chord. Associated fatigue cracks can reduce the structural capability of the upper side-of-body t-chord to a point where it cannot sustain limit load, which could adversely affect the structural integrity 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 Reference Revised Service Information \n\n\n\tUnited Airlines (UA) and All Nippon Airways (ANA) asked that we revise the NPRM to reference Boeing Alert Service Bulletin B787-81205- SB570018-00, Issue 002, because Boeing Alert Service Bulletin B787- 81205-SB570018-00, Issue 001, dated July 1, 2015, is currently being revised by Boeing. UA and ANA added that by including the revised service information for accomplishing the specified actions, requests for alternative methods of compliance (AMOCs) will be reduced. \n\tWe do not agree because the revised service information is not yet released. In an AD, we cannot refer to service information that does not exist because doing so violates Office of the Federal Register (OFR) regulations for approval of materials incorporated by reference in rules. To allow operators to use service information issued after publication of an AD, either we must supersede the AD to reference specific service information, or operators must request approval to use the new service information as an AMOC for the AD under the provisions of paragraph (j) of this AD. We consider addressing the unsafe condition as soon as possible a necessity. We might consider issuing a global AMOC if revised service information is approved. We have not changed this AD in this regard. \n\nRequest for Clarification of the Reason for the AD \n\n\n\tBoeing asked that we clarify that the proposed AD was prompted by reports indicating that the wing side-of-body stringer fittings that were installed with a faying surface mismatch beyond allowed tolerances were the upper stringer fittings. \n\tWe agree that clarification of the language describing what prompted the AD is necessary. We have changed the SUMMARY section of this final rule, as well as paragraph (e) of this AD, to \n\n((Page 3141)) \n\ninclude ''upper'' before ''stringer fittings.'' \n\nRequest for Clarification of Certain Language in the Discussion Section \n\n\n\tBoeing asked that we clarify the Discussion section of the NPRM, which stated that the faying surface mismatch produces a gouge. Boeing requested that we revise this wording to indicate that a gouge produced from a faying surface mismatch is a possibility, not a certainty. \n\tWe do not agree that the description in the Discussion section of the NPRM is inaccurate, because excessive cutter mismatch will produce a gouge in the mating surface eventually. In addition, the Discussion section of NPRMs is not fully repeated in final rules. Therefore, we have not changed this AD in this regard. \n\nRequest for Clarification of Corrective Actions \n\n\n\tBoeing asked that we clarify the description of the corrective actionsin the ''Related Service Information under 1 CFR part 51'' section of the NPRM by distinguishing certain conditions associated with the various corrective actions. \n\tWe agree that clarification of the language is necessary. The ''Related Service Information under 1 CFR part 51'' section in an AD simply describes the various actions in the service information; it does not describe the detailed requirements with specific corrective actions for specific inspection findings. Therefore, we have changed that section in this final rule to simply list the different actions provided in Boeing Alert Service Bulletin B787-81205-SB570018-00, Issue 001, dated July 1, 2015. \n\nRequest for Clarification of Certain Language in FAA's Determination Section \n\n\n\tBoeing asked that the word ''other'' be removed from the ''FAA's Determination'' section of the NPRM, which specifies that the unsafe condition ''is likely to exist or develop in other products of the same type design.'' Boeing stated that the unsafe condition resulted from a quality escapement applicable to specific line numbers, and therefore is not likely to develop in other products of the same type design (i.e., the entire 787-8 fleet). \n\tWe do not agree to remove the word ''other'' from the specified sentence. In 14 CFR 39.5, which defines the reason for issuing ADs, it states that an AD addresses ''a product'' when the unsafe condition is likely to exist or develop in ''other products'' of the same type design. The product addressed by an AD refers to the airplane(s) associated with the incident or specific findings that prompted the AD. In this case, the ''other products'' extends to Model 787-8 airplanes that are identified in paragraph (c) of this AD--that is, airplanes identified in Boeing Alert Service Bulletin B787-81205-SB570018-00, Issue 001, dated July 1, 2015--not the entire fleet. We have not changed this AD in this regard. \n\nRequest for Clarification of Compliance Time \n\n\n\tBoeing asked that we change the compliance time wording in paragraph (g) of the proposed AD for clarification by referring to Boeing Alert Service Bulletin B787-81205-SB570018-00, Issue 001, dated July 1, 2015, instead of specifying the actual compliance time. \n\tWe do not agree with the request. Paragraph (g) of the proposed AD (which is retained in this final rule) provides the compliance time (before the accumulation of 18,000 total flight cycles, or within 13 years after the effective date of this AD, whichever occurs first) because the Accomplishment Instructions of the service information do not provide a compliance time for the inspection. We have not changed this AD regarding this issue. \n\nRequest for Clarification of Type of Inspections and Applicable Corrective Actions \n\n\n\tBoeing asked that we clarify the description of the inspections specified in paragraphs (g)(1), (g)(2), and (g)(3) of the proposed AD as follows: (1) Do a detailed inspection for a machine mismatch condition of the stringer 1fitting faying surface; (2) Do a detailed inspection of the faying surface of the aluminum T-chord common to stringer 1 fitting for fretting damage; and (3) Do an eddy current inspection for cracking of the fastener holes common to stringer fittings 1 and 5 through 11. Boeing stated that this will more closely match the information and sequence of the inspections specified in the referenced service information. \n\tWe agree with the commenter's request to clarify the inspection language specified in paragraphs (g)(1), (g)(2), and (g)(3) of this AD, for the reasons provided. We have clarified those paragraphs accordingly. \n\tBoeing asked that we revise paragraph (h) of the proposed AD to clarify the corrective actions. The commenter defined four corrective actions (which are also defined in the service information). \n\tWe agree with the commenter's request in part. We do not agree to clarify the corrective actions because the actions described by the commenter are for the inspections required by paragraph (g) of this AD, and are clearly specified in Boeing Alert Service Bulletin B787-81205- SB570018-00, Issue 001, dated July 1, 2015. Those corrective actions are identified in paragraph (g) of this AD as, simply, ''corrective actions,'' and are further defined by reference to Boeing Alert Service Bulletin B787-81205-SB570018-00, Issue 001, dated July 1, 2015. However, we do agree to change the title of paragraph (h) of this AD to specify ''Modification, Inspection, and Repair'' to encompass the requirements specified in paragraph (h) of this AD. \n\nRequest for Clarification of RC Steps \n\n\n\tTo ensure that all provisions within the RC steps for contacting Boeing are captured, Boeing requested that we revise paragraph (i) of the proposed AD to refer to repair of the ''applicable condition'' instead of just ''cracking.'' \n\tWe do not agree with the commenter's request. Boeing Alert Service Bulletin B787-81205-SB570018-00, Issue 001, dated July 1, 2015, specifies contacting Boeing if there is a crack; corrective actions for other discrepancies are provided within the service information. \n\tBoeing also asked that we add the following exception in paragraph (i) of the proposed AD: \n\n\n\tAdditionally, where Boeing Alert Service Bulletin B787-81205- SB570018-00, Issue 001, dated July 1, 2015, specifies a compliance time ''after the original issue date of this service bulletin,'' this AD requires compliance within the specified compliance time after the effective date of this AD. \n\n\n\tWe do not agree to include the compliance time exception. As explained previously, the compliance times in this AD are defined using specific times instead of referring to the service information. Therefore, there are no exceptions to the service information regarding the compliance times in this AD. We have not changed this AD regarding this issue. \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\n((Page 3142)) \n\n\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 Service Bulletin B787-81205-SB570018-00, Issue 001, dated July 1, 2015. The service information describes procedures for inspection of the left and right hand side stringer 1 fittings for faying surface mismatch common to the side-of-body rib chord, replacement of the stringer 1 fitting, and removal and replacement of the clearance fit fasteners common to the side-of-body fittings and upper side-of-body rib chord with tapered sleeve bolts from stringer 5 to stringer 11. 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 5 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 -------------------------------------------------------------------------------------------------------------------------------------------------------- Inspections and modification........... 144 work-hours x $85 per hour = $12,240........................ $100,079 $112,319 $561,595 -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\n\n\tWe estimate the following costs to do any necessary corrective action for fretting damage or cutter mismatch based on the results of the inspection. We have no way of determining the number of aircraft that might need these corrective actions: \n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per \n\tAction Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Repair for fretting damage or 9 work-hours x $85 per hour = $765........... $0 $765 \n\tcutter mismatch. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that enables us to provide cost estimates for the crack repair 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.