AD 2013-06-05

We are superseding an existing airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. That AD currently requires repetitive inspections of the aft attach lugs of the elevator tab control mechanisms, and replacement of any discrepant elevator tab control mechanism. This new AD requires replacing the left and right elevator tab control mechanisms with elevator tab control mechanisms that have the modified attach lugs, which would terminate the existing requirements. This AD was prompted by reports of failure of the aft attach lugs on the elevator tab control mechanisms, which resulted in severe elevator vibration; and reports of gaps in elevator tab control mechanisms and analysis indicating that additional elevator tab control mechanisms might have bearings that will come loose. We are issuing this AD to prevent discrepancies in the aft attach lugs of the elevator tab control mechanism, which could result insevere elevator and tab vibration. Consequent structural failure of the elevator or horizontal stabilizer could result in loss of structural integrity and aircraft control.

Final rule.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n\n\n0 2. The FAA amends Sec. 39.13 by removing airworthiness directive (AD) 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010), and adding the following new AD: \n\n2013-06-05 The Boeing Company: Amendment 39-17402; Docket No. FAA- 2012-0994; Directorate Identifier 2012-NM-119-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective May 9, 2013. \n\n(b) Affected ADs \n\n\n\tThis AD supersedes AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). \n\n(c) Applicability \n\n\n\tThis AD applies to all The Boeing Company Model 737-600, -700, - 700C, -800, -900, and -900ER series airplanes, certificated in any category. \n\n(d) Subject \n\n\n\tJoint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 27, Flight Controls. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of failure of the aft attach lugs on the elevator tab control mechanisms, which resulted in severe elevator vibration. This AD also results from reports of gaps in elevator tab control mechanisms and analysis that additional elevator tab control mechanisms might have bearings that will come loose. We are issuing this AD to prevent discrepancies in the aft attach lugs of the elevator tab control mechanism, which could result in severe elevator and tab vibration. Consequent structural failure of the elevator or horizontal stabilizer could result in loss of structural integrity and aircraft control. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Retained Repetitive Inspections for Group 1 Airplanes \n\n\n\tThis paragraph restates the requirementsof paragraph (g) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For Group 1 airplanes, as identified in Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010: Except as required by paragraph (h) of this AD, within 12 days after April 29, 2010 (the effective date of AD 2010-09-05, Amendment 39-16270 (75 FR 21499, April 26, 2010)), do a detailed inspection for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010. Repeat the inspection thereafter at intervals not to exceed 300 flight hours. Doing the replacement specified in paragraph (l) of this AD before September 9, 2010 (the effective date of AD 2010-17-19), terminates the requirements of this paragraph. Doing the inspection required by paragraph (n) of this AD terminates the requirements of this paragraph. \n\n(h) Retained Extended Twin Operations (ETOPS) Flight Provisions \n\n\n\tThis paragraph restates the requirements of paragraph (h) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For Group 1 airplanes as identified in Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010: Beginning 7 days after April 29, 2010 (the effective date of AD 2010-09-05, Amendment 39-21499 (75 FR 21499, April 26, 2010)), no person may operate an airplane on an ETOPS flight unless the initial inspection required by paragraph (g) of this AD has been accomplished. Doing the inspection required by paragraph (n) of this AD terminates the requirements of this paragraph. \n\n(i) Retained One-Time Inspection for Group 2, Configuration 1, Airplanes \n\n\n\tThis paragraph restates the requirements of paragraph (i) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For Group 2, Configuration 1, airplanes as identified in Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010: Within30 days after April 29, 2010 (the effective date of AD 2010-09-05, Amendment 39-16270 (75 FR 21499, April 26, 2010)), do a one-time detailed inspection for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010. Doing the inspection required by paragraph (n) of this AD terminates the requirements of this paragraph. \n\n(j) Corrective Actions for Paragraphs (g), (i), and (k) of This AD \n\n\n\tThis paragraph restates the requirements of paragraph (j) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). If, during any inspection required by paragraph (g), (i), or (k) of this AD, any discrepancy is found, before further flight, replace the elevator tab control mechanism by doing the actions specified in paragraphs (j)(1) and (j)(2) of this AD. \n\t(1) Do a detailed inspection for discrepancies of thereplacement elevator tab control mechanism; and, if no discrepancy is found, install the replacement elevator tab control mechanism; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010. If any discrepancy is found, then that elevator tab control mechanism cannot be installed and the actions specified in this paragraph must be done before further flight on another replacement elevator tab control mechanism. \n\t(2) Re-inspect the installed elevator tab control mechanism using the inspection procedure specified in paragraph (i) of this AD. \n\n(k) Retained Repetitive Inspections for Certain Group 2, Configuration 1, Airplanes \n\n\n\tThis paragraph restates the requirements of paragraph (k) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For Group 2, Configuration 1, airplanes as identified in Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010, on which the elevator tab control mechanism isreplaced with a mechanism other than a new, Boeing-built mechanism: Within 300 flight hours after doing the replacement, do a detailed inspection for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737- 27A1297, dated April 16, 2010. Repeat the inspection thereafter at intervals not to exceed 300 flight hours. Doing the replacement specified in paragraph (l) of this AD before September 9, 2010 (the effective date of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010)), is terminating action for this paragraph. Doing the inspection required by paragraph (n) of this AD terminates the requirements of this paragraph. \n\n(l) Terminating Action Credit for Paragraphs (g), (i), and (k) of This AD \n\n\n\tThis paragraph restates the requirements of paragraph (l) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). Replacing an elevator tab control mechanism with a new, Boeing-built mechanism before September 9, 2010 (the effective date of AD 2010- 17-19), as specified in paragraphs (l)(1) and (l)(2) of this AD, terminates the inspections required by paragraphs (g), (i), and (k) of this AD. Replacement of the elevator tab control mechanism on or after September 9, 2010 (the effective date of AD 2010-17-19), does not terminate the inspections required by paragraphs (g), (i), and (k) of this AD. \n\n\n\tNote 1 to paragraph (l) of this AD: Additional guidance can be found in paragraphs 3.B.7.b.(1)(a)(1) and 3.B.7.b.(1)(a)(2) of the Accomplishment Instructions of Boeing Alert Service Bulletin \n\n((Page 20233)) \n\n737-27A1297, dated April 16, 2010, for establishing whether the mechanism is Boeing built. \n\n\n\t(1) Do a detailed inspection for discrepancies of the new, Boeing-built replacement elevator tab control mechanism; and, if no discrepancy is found, install the replacement elevator tab control mechanism; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010. If any discrepancy is found, then that elevator tab control mechanism cannot be installed and the actions specified in this paragraph must be done on another new, Boeing-built replacement elevator tab control mechanism. \n\t(2) Re-inspect the installed elevator tab control mechanism using the inspection procedure specified in paragraph (i) of this AD. \n\n(m) Retained Reporting for Paragraphs (g), (i), and (k) of This AD \n\n\n\tThis paragraph restates the requirements of paragraph (m) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For airplanes identified in Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010: At the applicable time specified in paragraph (m)(1) or (m)(2) of this AD, submit a report of any findings (positive and negative) of the first inspection required by paragraphs (g), (i), and (k) of this AD, and any positive findings from the repetitive inspections required by paragraphs (g) and (k) of this AD, to Boeing Commercial Airplanes Group, Attention: Manager, Airline Support, email: rse.boecom@boeing.com. The report must include the inspection results including a description of any discrepancies found, the airplane line number, and the total number of flight cycles and flight hours accumulated on the airplane. \n\t(1) If the inspection was done on or after April 29, 2010 (the effective date of AD 2010-09-05, Amendment 39-16270 (75 FR 21499, April 26, 2010)): Submit the report within 10 days after the inspection. \n\t(2) If the inspection was done before April 29, 2010 (the effective date of AD 2010-09-05, Amendment 39-16270 (75 FR 21499, April 26, 2010)): Submit the report within 10 days after April 29, 2010 (the effective date of AD 2010-09-05). \n\n(n) Retained Repetitive Inspections \n\n\n\tThis paragraph restates the requirements of paragraph (n) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For airplanes having line numbers 1 through 3909 inclusive: At the applicable time specified in paragraph (n)(1), (n)(2), or (n)(3) of this AD, do a detailed inspection for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010. For Groups 1 and 2 airplanes identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010, repeat the inspection thereafter at intervals not to exceed 300 flight hours, except as provided by paragraph (t)(2) of this AD. For Group 3 airplanes identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010, repeat the inspection thereafter at intervals not to exceed 1,800 flight hours, except as required by paragraphs (p) and (t)(2) of this AD. Doing the inspection specified in this paragraph terminatesthe requirements of paragraphs (g), (h), (i), and (k) of this AD. \n\t(1) For Group 1 airplanes identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010: Within 300 flight hours after doing an inspection in accordance with Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010, or within 30 days after September 9, 2010 (the effective date of AD 2010-17- 19, Amendment 39-16413 (75 FR 52242, August 25, 2010)), whichever occurs later. \n\t(2) For Group 2 airplanes identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010: At the later of the times specified in paragraphs (n)(2)(i) and (n)(2)(ii) of this AD. \n\t(i) Before the accumulation of 2,000 total flight cycles or 4,000 total flight hours, whichever occurs first. \n\t(ii) Within 14 days after September 9, 2010 (the effective date of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010)). \n\t(3) For Group 3 airplanes identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010: Within 180 days or 1,800 flight hours after September 9, 2010 (the effective date of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010)), whichever occurs first. \n\n(o) Retained Corrective Actions for Paragraphs (n) and (p) of This AD \n\n\n\tThis paragraph restates the requirements of paragraph (o) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). If, during any inspection required by paragraph (n) or (p) of this AD, any discrepancy is found, before further flight, replace the elevator tab control mechanism by doing the actions specified in paragraphs (o)(1) and (o)(2) of this AD. \n\t(1) Do a detailed inspection for discrepancies of the replacement elevator tab control mechanism; and, if no discrepancy is found, install the replacement elevator tab control mechanism; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010. Ifany discrepancy is found, then that elevator tab control mechanism cannot be installed and the actions specified in this paragraph must be done before further flight on another replacement elevator tab control mechanism. \n\t(2) Re-inspect the installed elevator tab control mechanism using the inspection procedure specified in paragraph (n) of this AD. \n\n(p) Retained Reduced Repetitive Inspection Interval for Group 3 Airplanes \n\n\n\tThis paragraph restates the requirements of paragraph (p) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For Group 3 airplanes as identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010, on which the elevator tab control mechanism is replaced during the actions required by paragraph (o) of this AD: Within 300 flight hours after doing the replacement, do a detailed inspection for discrepancies of the inboard and outboard aft attach lugs of the replaced elevator tab control mechanism, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010. Repeat the inspection of the replaced elevator tab control mechanism thereafter at intervals not to exceed 300 flight hours, except as provided by paragraph (t)(2) of this AD. \n\n(q) Retained Credit for Previous Action \n\n\n\tThis paragraph restates the provisions specified in paragraph (q) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For Group 1 airplanes as identified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010: Inspections done in accordance with Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010, are acceptable for compliance with only the initial inspection required by paragraph (n) of this AD. \n\n(r) Retained Reporting for Paragraphs (n) and (p) of This AD \n\n\n\tThis paragraph restates the requirements of paragraph (r) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). For airplanes having line numbers 1 through 3909 inclusive: At the applicable time specified in paragraph (r)(1) or (r)(2) of this AD, submit a report of any findings (positive and negative) of the first inspection required by paragraphs (n) and (p) of this AD, except for airplanes on which a report required by paragraph (m) of this AD has been submitted, only submit positive findings; and submit a report of any positive findings from the repetitive inspections required by paragraphs (n) and (p) of this AD; to Boeing Commercial Airplanes Group, Attention: Manager, Airline Support, email: rse.boecom@boeing.com. The report must include the inspection results including a description of any discrepancies found, the airplane line number, and the total number of flight cycles and flight hours accumulated on the airplane. \n\t(1) If the inspection was done on or after September 9, 2010 (the effective date of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010)): Submit the report within10 days after the inspection. \n\t(2) If the inspection was done before September 9, 2010 (the effective date of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010)): Submit the report within 10 days after September 9, 2010 (the effective date of AD 2010-17-19). \n\n(s) Retained Provision Regarding Not Returning Parts \n\n\n\tThis paragraph restates the provision specified in paragraph (s) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). Although Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010; and Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010; specify to return the affected elevator tab control mechanism to the manufacturer, this AD does not require the return of the part to the manufacturer. \n\n((Page 20234)) \n\n(t) Retained Parts Installation Limitations \n\n\n\tThis paragraph restates the requirements of paragraph (t) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010), with revised limitations. As of September 9, 2010 (the effective date of AD 2010-17-19), and until the replacement required by paragraph (u) of this AD for airplanes with line numbers 1 through 3909 inclusive, or until the effective date of this new AD for airplanes with line numbers 3910 and subsequent, as applicable: Comply with the conditions specified in paragraphs (t)(1) and (t)(2) of this AD. \n\t(1) No person may install an elevator tab control mechanism, part number (P/N) 251A2430-(), on any airplane, unless the mechanism has been inspected before and after installation using the inspection procedures specified in paragraphs (o)(1) and (o)(2) of this AD, and no discrepancies have been found. \n\t(2) An elevator tab control mechanism, P/N 251A2430-(), may be installed, provided that the inspection specified in paragraph (n) of this AD is done within 300 flight hours after doing the installation, and that the inspection specified in paragraph (n) of this AD is repeated thereafter at intervals not toexceed 300 flight hours. \n\n(u) New Replacement \n\n\n\tFor airplanes having line numbers 1 through 3909 inclusive: Within 60 months after the effective date of this AD, replace the left and right elevator tab control mechanisms with elevator tab control mechanisms that have new machined aft attach lugs, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-27-1300, dated April 16, 2012. This replacement terminates the requirements of paragraphs (g) through (t) of this AD. Although Boeing Service Bulletin 737-27-1300, dated April 16, 2012, specifies submitting a report, there is no requirement to report completion of the replacement required by paragraph (u) of this AD. \n\n(v) New Parts Installation Prohibition \n\n\n\tAs of the effective date of this AD, no person may install, on any airplane identified in paragraph (v)(1) or (v)(2) of this AD, an elevator tab control mechanism having P/N 251A2430-13, -14, -15, - 16, -17, -18, -101, -102, -103, -104, -105,or -106. \n\t(1) Airplanes on which the replacement in paragraph (u) of this AD has been accomplished. \n\t(2) Airplanes with line numbers 3910 and subsequent. \n\n(w) Paperwork Reduction Act Burden Statement \n\n\n\tA federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to theFAA at: 800 Independence Ave. SW., Washington, DC 20591, Attn: Information Collection Clearance Officer, AES-200. \n\n(x) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD. Information may be emailed to 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. \n\t(3) An AMOC that provides an acceptable level of safety may be used for anyrepair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\t(4) AMOCs approved for AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010), are approved as AMOCs for the corresponding provisions of this AD. The expiration of the AMOCS to AD 2010-17-19, as specified in the service information identified in paragraphs (x)(4)(i) and (x)(4)(ii) of this AD, is extended to remain valid until accomplishment of the requirements of paragraph (u) of this AD. \n\t(i) Boeing Alert Service Bulletin 737-27A1299, dated July 1, 2011 (which is not incorporated by reference in this AD). \n\t(ii) Boeing Alert Service Bulletin 737-27A1299, Revision 1, dated April 16, 2012 (which is not incorporated by reference in this AD). \n\n(y) Related Information \n\n\n\tFor more information about this AD, contact Kelly McGuckin, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: 425-917-6490; fax: 425-917- 6590; email: kelly.mcguckin@faa.gov. \n\n(z) Material Incorporated by Reference \n\n\n\t(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. \n\t(3) The following service information was approved for IBR on May 9, 2013. \n\t(i) Boeing Service Bulletin 737-27-1300, dated April 16, 2012. \n\t(ii) Reserved. \n\t(4) The following service information was approved for IBR on September 9, 2010 (75 FR 52242, August 25, 2010). \n\t(i) Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010. \n\t(ii) Reserved. \n\t(5) The following service information was approved for IBR on April 29, 2010 (75 FR 21499, April 26, 2010). \n\t(i) Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010. \n\t(ii) Reserved. \n\t(6) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544- 5000, extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com. \n\t(7) You may view this service information at FAA, You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. \n\t(8) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information onthe availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). (That AD superseded AD 2010-09-05, Amendment 39-16270 (75 FR 21499, April 26, 2010).) That AD applies to the specified products. The NPRM published in the Federal Register on September 20, 2012 (77 FR 58330). That NPRM proposed to continue to require repetitive inspections of the aft attach lugs of the elevator tab control mechanisms, and replacement of any discrepant elevator tab control mechanism. That NPRM also proposed to require replacing the left and right elevator tab control mechanisms with elevator tab control mechanisms that have modified attach lugs, which would terminate the existing requirements. \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 (77 FR 58330, September 20,2012) and the FAA's response to each comment. Aviation \n\n((Page 20230)) \n\nPartners Boeing stated that the installation of winglets per supplemental type certificate (STC) ST00830SE (http://rgl.faa.gov/ Regulatory--and--Guidance--Library/rgstc.nsf/0/ 408e012e008616a7862578880060456c/$FILE/ST00830SE.pdf) does not affect the accomplishment of the manufacturer's service instructions. United Airlines stated that it agrees with the proposal. \n\nRequest To Remove Parts Installation Prohibition \n\n\n\tBoeing requested that we remove paragraph (v) (''New Parts Installation Prohibition'') from the NPRM (77 FR 58330, September 20, 2012). Boeing stated that we should allow installation of mechanisms having part number (P/N) 251A2430-13, -14, -15, -16, -17, or -18 within the compliance time specified in the NPRM, and allow continued operations under the provisions of Boeing Alert Service Bulletin 737- 27A1297, Revision 1, dated August 2, 2010; and AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). Likewise, Boeing requested that we allow installation of mechanisms having P/N 251A2430-101, -102, -103, -104, -105, or -106 within the compliance time specified in the NPRM, and allow continued operations under the provisions of Boeing Alert Service Bulletin 737-27A1299, dated July 1, 2011; and Boeing Alert Service Bulletin 737-27A1299, Revision 1, dated April 16, 2012; which are approved as alternative methods of compliance (AMOCs) to AD 2010-17-19. The commenter stated that paragraph (v) of the NPRM (which would prohibit installing those parts as of the effective date of the AD) would reduce operator flexibility by prematurely forcing incorporation of Boeing Service Bulletin 737-27-1300, dated April 16, 2012, before the end of the 60-month compliance period. The commenter added that this also would prevent incorporation of Boeing Alert Service Bulletin 737-27A1299, Revision 1, dated April 16, 2012, which Boeing plans to recommend that operators incorporate by April 2013 if they cannot complete terminating action by that date. \n\tWe partially agree with the request. We agree to allow operators the continued flexibility of using the noted mechanisms in accordance with the provisions of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010), or AMOCs specified in Boeing Alert Service Bulletin 737-27A1299, dated July 1, 2011, and Boeing Alert Service Bulletin 737- 27A1299, Revision 1, dated April 16, 2012, before the replacement specified in paragraph (u) of this AD. That replacement is required for airplanes with line numbers 1 through 3909 inclusive. This will provide flexibility and still maintain an adequate level of safety. We disagree, however, with deleting paragraph (v) of this AD. The referenced mechanisms have contributed to a known unsafe condition and must not be used as a spare after the incorporation of paragraph (u) of this AD (which requires replacement of these mechanisms). We have changed paragraph (v) in this final rule to limit the prohibition against installing the referenced parts to a time after the requirements of paragraph (u) have been accomplished for airplanes with line numbers 1 through 3909 inclusive. For airplanes with line numbers 3910 and subsequent, mechanisms with modified aft attach lugs have been installed in production; for these airplanes, the parts referenced in paragraph (v) of this AD are prohibited from installation as of the effective date of this AD. \n\nRequest To Revise Identity of Referenced Mechanisms \n\n\n\tBoeing requested that we revise paragraph (t) of the NPRM (77 FR 58330, September 20, 2012) to limit the affected mechanisms to mechanism P/Ns ''251A2430-13, -14, -15, -16, -17, or -18.'' Boeing stated that this paragraph should not apply to P/N 251A2430-23 and -24 mechanisms, because their installation is terminating action for the NPRM. The commenter added that paragraph (t) of the NPRM also does not apply to the -101, -102, -103, -104, -105, or -106 mechanism, which have a minimum proposed repetitive inspection requirement of 800 flight hours (not 300 flight hours). \n\tWe do not agree to incorporate the requested changes in the final rule. Paragraph (t) of the AD restates the requirements of paragraph (t) of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). The replacement required by paragraph (u) of this new AD terminates the requirements of AD 2010-17-19, including paragraph (t). The FAA approved an AMOC to AD 2010-17-19 for Boeing Alert Service Bulletin 737-27A1299, dated July 1, 2011; and Boeing Alert Service Bulletin 737-27A1299, Revision 1, dated April 16, 2012; for the requirements of paragraph (t) for the -101, -102, -103, -104, -105, and -106 mechanisms; as specified in paragraph (x)(4) of this AD, that AMOC still applies. We have not changed the final rule regarding this issue. \n\nRequest To Remove Compliance Time Restriction \n\n\n\tBoeing requested that we revise the NPRM (77 FR 58330, September 20, 2012) to delete''and until the effective date of this new AD'' from the second sentence of paragraph (t) of the proposed AD. The commenter stated that operators should be allowed to install P/N 251A2430-13, -14, -15, -16, -17, or -18 mechanisms within the compliance period specified in the NPRM and continue operations under the provisions of Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010; and AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). \n\tWe agree with the request and have revised paragraph (t) accordingly in this final rule. We are also clarifying the requirements of paragraph (t) in this final rule for line numbers 3910 and subsequent, which are produced with part numbers that terminate the requirements of AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). \n\nRequest To Revise Cost Estimate \n\n\n\tDelta requested that we revise the estimated costs in the NPRM (77 FR 58330, September 20, 2012). Delta stated that the cost informationprovided in the NPRM does not reflect the most current information available in Boeing Service Bulletin 737-27-1300 Information Notice (IN) 01, dated April 19, 2012, which gives a total of 16 task hours for each installed mechanism (32 hours per airplane) and 10 hours for each modified component (20 hours per airplane). \n\tWe agree, and have revised the cost estimate accordingly in this final rule. \n\nRequest To Extend Compliance Time for Related AMOC \n\n\n\tDelta, American, and Boeing requested that we revise the NPRM (77 FR 58330, September 20, 2012) to extend the compliance time for the AMOC associated with AD 2010-17-19, Amendment 39-16413 (75 FR 52242, August 25, 2010). American and Delta stated that we should allow that AMOC to remain valid until the accomplishment of the actions specified in paragraph (u) of the NPRM to allow the fullest benefit of the clip installation. Boeing stated that paragraph (v) of the NPRM conflicts with paragraph (x)(3) of the NPRM regarding the AMOC. Delta stated that Boeing Alert Service Bulletin 737-27A1299, Revision 1, dated April 16, 2012, notes that the AMOC was intended as interim action and has an \n\n((Page 20231)) \n\nexpiration date of June 30, 2016; Delta concluded that AMOC approval would therefore expire before the 60-month compliance time specified in the NPRM for the replacement in paragraph (u) of the NPRM. \n\tWe agree with the requests, for the reasons provided by the commenters. We have changed paragraph (x)(4) in this final rule to extend the expiration of the referenced AMOCs. \n\nRequest To Clarify Reporting Requirement \n\n\n\tDelta requested that we revise the NPRM (77 FR 58330, September 20, 2012) to clarify the required methods and requirements for reporting completion of the retrofit. Delta noted that paragraph (u) of the NPRM specifies to replace the elevator tab control mechanism in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-27- 1300, dated April 16, 2012. Delta stated that the last step of those instructions specifies reporting retrofit completions to Boeing using the service request application on MyBoeingFleet.com. Delta noted that the NPRM does not specifically identify any requirement to report the tab mechanism retrofit completions. \n\tWe agree to clarify the reporting requirements: Although Boeing Service Bulletin 737-27-1300, dated April 16, 2012, specifies submitting a report, there is no new reporting requirement to report completion of the replacement required by paragraph (u) of this AD. We have changed paragraph (u) in this final rule to state that there is no reporting requirement as part of the replacement. \n\nRequest To Revise Applicability \n\n\n\tAmerican requested that we revise paragraph (c) (''Applicability'') of the NPRM (77 FR 58330, September 20, 2012) to match the applicability of paragraph (u) (mechanism replacement) of the NPRM (which applied to line numbers 1 through 3909 inclusive). American stated that Boeing Alert Service Bulletin 737-27A1297, Revision 2, dated April 16, 2012; and Boeing Alert Service Bulletin 737-27A1299, Revision 1, dated April 16, 2012; have been revised to limit the effectivity of this issue. \n\tWe disagree with the request to revise the applicability. The applicability of this final rule includes the effectivity of those service bulletins. But the applicability of this AD extends to all Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes to account for spares that might also be installed on those airplanes, as specified in paragraph (v) (''New Parts Installation Prohibition'') in this final rule. We have not revised the final rule further regarding this issue. \n\nExplanation of Change Made to This AD \n\n\n\tWe have added paragraph (x)(3) in this final rule to specify that an AMOC that provides an acceptable level of safety may be used for any repair required by this AD if that repair is approved by the Boeing Commercial Airplanes Organizational Designation Authorization (ODA) that has been authorized by the Manager of the Seattle Aircraft Certification Office to make those findings. \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 and minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM (77 FR 58330, September 20, 2012) for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM (77 FR 58330, September 20, 2012). \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 1,096 airplanes of U.S. registry. We estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per product ---------------------------------------------------------------------------------------------------------------- Retained actions.............. 7 work-hours x $85 $0................... $595 per inspection cycle. \n\tper hour = $595 per \n\tinspection cycle. Mechanism replacement (one 32 work-hours x $85 $58,579\1\ $1,140 $62,439 per airplane. \n\toption for terminating per hour = $2,720. (installation kit). \n\taction). Mechanism modification and 52 work-hours x $85 $5,858 (for the $13,563 per airplane. \n\treplacement (one option for per hour = $4,420. modification) $1,140 \n\tterminating action). (installation kit) \n\t$2,145 (tooling\2\). ---------------------------------------------------------------------------------------------------------------- \1\ This is the estimated cost for both a left and right mechanism. Boeing is planning a seed/exchange program \n\tso operators are not forced to purchase a new mechanism. \2\ Per the Boeing service information, tooling is available from Boeing for $90 per day. \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 withinthe 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\n((Page 20232)) \n\n\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 RegulatoryFlexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.