Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM published in the Federal Register on January 19, 2011 (76 FR 3054). That NPRM proposed to require revising the maintenance program to update inspection requirements to detect fatigue cracking of principal structural elements (PSEs). \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 (76 FR 3054, January 19, 2011) and the FAA's response to each comment. \n\nRequest To Refer to Latest Service Information \n\n\n\tBoeing and Japan Airlines (JAL) requested that we revise the NPRM (76 FR 3054, January 19, 2011) to refer to two new revisions of Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, of the Boeing 777 Maintenance Planning Data (MPD)Document, published after we issued the NPRM. Boeing stated that both revisions contain the same structures airworthiness limitations (AWL) data, but were revised for reasons that did not affect the data in Subsection B, Airworthiness Limitations-- Structural Inspections of that document, which was specified in the NPRM. \n\tWe agree with the request to refer to the later service information. We have changed this final rule to refer to Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document to this AD. (Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision January 2010, of the Boeing 777 Maintenance Planning Data (MPD) Document was specified in the NPRM (76 FR 3054, January 19, 2011).) (Subsection B, Airworthiness Limitations--Structural Inspections, of Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, of the Boeing 777 Maintenance Planning Data (MPD) Document is identical to the January 2010 revision.) We have changed paragraph (g) in this final rule accordingly. \n\n((Page 21430)) \n\nRequest To Revise Inspection Requirements for Certain Airplanes \n\n\n\tJAL requested that, for certain airplanes, we revise paragraph (g) of the NPRM (76 FR 3054, January 19, 2011) to require inspection procedures and intervals as determined by the damage tolerance rating check form, rather than Section 2, Structural Inspection Program, of the Boeing 777 Maintenance Planning Data (MPD) Document. JAL acknowledged that Section 2 of this MPD document usually incorporates recommended inspection procedures and intervals. JAL noted, however, that Section 2 in the latest revision of this MPD document includes data only for Model 777-200 series airplanes. Since no data are provided for the remaining airplanes affected by this AD (Model777- 200LR, -300, -300ER, and 777F series airplanes), JAL requested that those airplanes be excluded from the requirement until the MPD document includes relevant data. \n\tWe do not agree that the requested change is necessary, because the information regarding required inspection methods and intervals for these airplanes is provided in Subsection B, Airworthiness Limitations--Structural Inspections, of Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document. We have not changed the final rule regarding this issue. \n\nRequest To Retain Applicability \n\n\n\tBoeing also advised that the revised inspection requirements in Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document, affect only Model 777-200, -300, -300ER and -200LR series airplanes. Boeing reported that Section 9 of the Boeing 777F MPD document was previously developed based on the same damage tolerance methods and the same fleet and full-scale test data as those included in Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document. Boeing asserted, therefore, that Model 777F series airplanes should be included in the applicability of the NPRM (76 FR 3054, January 19, 2011) regardless of changes made to Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document. Including those airplanes will ensure the ability to obtain approval of potential future deviations for repairs or alternative inspections via alternative methods of compliance (AMOCs) (as described in paragraph (j) of this AD). Boeing made this comment in the event another party requested that we remove Model 777F series airplanes from the NPRM. \n\tWe acknowledge Boeing's concern, and agree that there is no reason to remove Model 777F series airplanes from the applicability specified in the NPRM (76 FR 3054, January 19, 2011). We have not changed the final rule regarding this issue. \n\nRequest To Remove Certain Advisory Circular Reference \n\n\n\tNote 2 of the NPRM (76 FR 3054, January 19, 2011) (paragraph (c)(2) of this AD) provided guidance on certain revised operator maintenance documents that include new inspections. Boeing requested that we remove the last sentence of that note, which stated that guidance for the determination can be found in FAA Advisory Circular (AC) 25.1529-1A, dated November 20, 2007 (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf). Boeing stated that this AC, as revised, applies only to airplanes below 7,500 pounds gross weight, so this AC no longer applies to Model 777 airplanes. \n\tWe agree with Boeing's request and rationale. We have revised paragraph (c) of this AD accordingly. \n\nRequest To Allow Additional Alternative Inspections and Intervals \n\n\n\tAmerican Airlines (AAL) and Boeing requested that we revise paragraph (h) of the NPRM (76 FR 3054, January 19, 2011), which prohibited alternative inspections or intervals except as specifically approved as AMOCs. To reduce the workload associated with requesting and approving AMOCs, the commenters requested that we include other specified procedures and intervals. \n\tStructurally Significant Items (SSIs) 53-00-I01, -I02, and -I03 define the entire fuselage skin as an SSI, and AAL was concerned that the NPRM (76 FR 3054, January 19, 2011) provided no guidance or information on how to address new and existing repairs. AAL surmised that any external doubler repair (past or future) would conceal a portion of the skin and would need AMOC approval for the inspection, which would be impossible to perform with the repair in place. AAL contended that any repair approved in accordance with section 25.571 of the Federal Aviation Regulations (14 CFR 25.571) or section 26.43(c) of the Federal Aviation Regulations (14 CFR 26.43(c)) has been addressed for fatigue and damage tolerance and would provide the level of safety desired by the NPRM. \n\tBoeing requested that we also allow alternative inspections and intervals specified in a later revision to Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, of the Boeing 777 Maintenance Planning Data (MPD) Document. Since Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, of the Boeing 777 Maintenance Planning Data (MPD) Document changes frequently and is FAA approved, no subsequent re-approval should be necessary via AMOC. Boeing also requested that we allow alternative inspections and intervals if certain damagetolerance requirements have been met in accordance with section 25.571(b) of the Federal Aviation Regulations (14 CFR 25.571(b)), or section 26.43(c) of the Federal Aviation Regulations (14 CFR 26.43(c)), or section 26.43(d) of the Federal Aviation Regulations (14 CFR 26.43(d)). \n\tWe disagree with the requests. Paragraph (h) in this AD requires compliance with the inspections unless AMOC approval is obtained as specified in paragraph (j) of this AD. Allowing later revisions of service documents in an AD violates Office of the Federal Register regulations for approving materials incorporated by reference. Affected operators may, however, request approval to use a later revision of referenced service information as an alternative method of compliance. In response to AAL's concern, operators must request a method of compliance to address new and existing repairs, under the provisions of paragraph (j) of the final rule. We have not changed the final rule regarding this issue. \n\nRequestTo Allow Optional Materials \n\n\n\tAAL requested that we revise the NPRM (76 FR 3054, January 19, 2011) to allow the optional use of BMS materials (sealants) permitted in Boeing Document D-590, the Boeing 777 Airplane Maintenance Manual, or the Boeing 777 Structural Repair Manual--instead of the specific materials specified in Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision January 2010, of the Boeing 777 Maintenance Planning \n\n((Page 21431)) \n\nData (MPD) Document. The use of alternative materials would allow for ready compliance if the current BMS materials were discontinued or improved. \n\tWe disagree with the request. The documents referenced by the commenter specify specific procedures to remove the sealant, rather than specific types of sealant. Further, some existing ADs including those related to Special Federal Aviation Regulation No. 88 (''SFAR 88''), Amendment 21-78 and subsequent Amendments 21-82 and21-83 (67 FR 72830, December 9, 2002), require specific sealants, which may be identified in the BMS specifications, but only certain sealants may be used to comply with SFAR88; operators are limited to the use of sealants approved by other AD actions in areas that overlap with this AD. The application of the sealants and materials in Subsection B, Airworthiness Limitations--Structural Inspections, of Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document, is often controlled by other ADs that mandate the use of certain sealants for Subsections D and E (of SFAR88). Operators may request an AMOC to use materials that have been determined to be acceptable for the various ADs applicable to Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document. We have not changed the final rule regarding this issue. \n\nRequest To Consider Future Boeing Delegated Compliance Organization Delegation \n\n\n\tBoeing requested that we revise paragraph (i)(3) of the NPRM (76 FR 3054, January 19, 2011), which provides information about AMOCs for repairs. Boeing requested that we also specify AMOCs for inspection methods, since there may be instances where the operator cannot conduct the inspection method specified in Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision January 2010, of the Boeing 777 Maintenance Planning Data (MPD) Document, identified in the NPRM. Although authority to approve AMOCs for supplemental inspections of baseline structure may not currently exist for the Boeing Delegated Compliance Organization (BDCO), Boeing suggested that including both repairs and inspections would allow for potential future expansion of delegation. \n\tWe disagreewith the request. The nondiscretionary basis for this type of delegation has not yet been developed. At present, the FAA must approve tasks that involve discretion, and may delegate only nondiscretionary tasks. In any event, any change to delegation authority in the future will not affect the AD. We have not changed the final rule regarding this issue. \n\nRequest To Clarify Allowable Equivalent Procedures \n\n\n\tAAL requested clarification of certain procedures. AAL observed the phrase ''refer to,'' used in Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision January 2010, of the Boeing 777 Maintenance Planning Data (MPD) Document, to specify certain chapters in an AMM. AAL noted that use of this phrase in service bulletins allows operators to use their equivalent procedures. AAL requested that we revise the NPRM (76 FR 3054, January 19, 2011) to state that equivalent procedures are acceptable where the phrase ''referto'' is used in Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document. \n\tWe disagree with the request. As the commenter noted, the phrase ''refer to'' is used in both AMMs and Boeing service bulletins. In a service bulletin, use of the phrase ''refer to'' generally means that a determination was made to permit operators' equivalent procedures where applicable, and use of the phrase ''as given in'' or ''in accordance with'' generally means that operators' equivalent procedures are not acceptable. But these definitions do not apply to Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document, for which operators' equivalent procedures are not specifically allowed. Under the provisions of paragraph (j) of this final rule, however, we will consider requests for approval to use different procedures, if sufficient data are submitted to substantiate that the procedures would provide an acceptable level of safety. We have not changed the final rule regarding this issue. \n\nRequest To Revise Compliance Time for Inspecting Replacement Parts \n\n\n\tBoeing requested that we revise paragraph (g) of the NPRM (76 FR 3054, January 19, 2011) to permit the compliance time thresholds to be reset for new replacement parts. Boeing asserted that Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document does not explicitly state that the inspection threshold for new parts starts when the part is replaced, and that other existing ADs include terminating action that zero-times certain fastener locations. Boeing made this request to allow operators to take credit for the younger life of those parts. \n\tWe agree that this change is necessary to accommodate new replacement parts. We have changed the initial compliance time accordingly in paragraph (g) of this AD. \n\nRequest To Revise Compliance Time for Reporting \n\n\n\tJAL noted that Section 9, ''Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs),'' D622W001-9, Revision July 2011, of the Boeing 777 Maintenance Planning Data (MPD) Document includes a reporting timeframe of 10 days after an inspection finding. JAL reported that these inspections are often accomplished during a heavy maintenance inspection where many inspections are accomplished over many days. Tracking all of the reporting at the time of return to service is easier rather than sending individual events occurring during the maintenance check. JAL therefore requested that the reporting time frames be revised from 10 days after a finding to 10 days after the airplane is returned to service. \n\tWe agree with JAL's request and rationale. We have added this reporting provision in paragraph (g) in the final rule. We have also added new paragraph (i) in this final rule to explain the requirements of the Paperwork Reduction Act, which requires agencies to consider the extent of the paperwork burden that will accompany any new rule. And we have reidentified subsequent paragraphs accordingly. \n\nRequest To Revise Compliance Time Determination \n\n\n\tBoeing noted that FAA Advisory Circular (AC) 120-93, dated November 20, 2007 (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf) provides \n\n((Page 21432)) \n\nguidance for addressing damage tolerance inspection requirements for repairs and alterations to certain removable structural components. Boeing requested that we revise the NPRM (76 FR 3054, January 19, 2011) to add a provision to paragraph (g) of the NPRM, allowing FAA AC 120-93 as a means to establish compliance times for rotable parts where the data are not available. \n\tWe disagree. That ACprovides guidance and an acceptable means for developing the age of removable parts for the purpose of determining compliance times for repairs and alterations. If the actual age, flight hours, and flight cycles are unknown for a part affected by the AD, we would consider the operator's request for an AMOC. This allows Boeing and operators the option to propose methods in detail that use FAA AC 120-93, dated November 20, 2007 (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf), for guidance. We have not changed the final rule regarding this issue. \n\nRequest To Clarify Certain PSEs \n\n\n\tWang Jian requested clarification of the identity of certain PSEs. Attached to this comment was a copy of a page from the Boeing 777F Structural Repair Manual, which identified primary structure for repair classification. From this page, the commenter observed that the main deck floor panels are identified as PSEs on Model 777F series airplanes, but not on other aircraft suchas Model 747-400F series airplanes. \n\tAlthough the commenter's question concerning the PSE differences between the Model 747 and 777 is not related to the inspections required by this AD, the intent of the question may be explained in more detail in FAA Advisory Circular (AC) 25.1529-1A, dated November 20, 2007 (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf). We have not changed the final rule regarding this issue. \n\nExplanation of Additional Changes Made to This AD \n\n\n\tWe have redesignated Note 1 and Note 2 of the NPRM (76 FR 3054, January 19, 2011) as paragraphs (c)(1) and (c)(2) of this AD respectively. These changes have not changed the intent of this AD. \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 also determined that these changes will not increase the economic burden on any operatoror increase the scope of the AD. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD will affect 153 airplanes of U.S. registry. We 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 ---------------------------------------------------------------------------------------------------------------- Maintenance program revision.......... 1 work-hour x $85 per hour = $0 $85 $13,005 \n\t$85. ---------------------------------------------------------------------------------------------------------------- \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.For 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.