AD 2011-14-02

The FAA is superseding an existing airworthiness directive (AD) that applies to all Model 767 airplanes. The existing AD currently requires repetitive detailed and high frequency eddy current (HFEC) inspections of the station (STA) 1809.5 bulkhead for cracking, and corrective actions if necessary. This AD expands the inspection area to include the vertical inner chord at STA 1809.5. This AD results from reported fatigue cracking in the vertical inner chord and the forward outer chord while doing the detailed inspection of the horizontal inner chord at STA 1809.5. We are issuing this AD to detect and correct fatigue cracking in the bulkhead structure at STA 1809.5 and the vertical inner chord at STA 1809.5, which could result in failure of the bulkhead structure for carrying the flight loads of the horizontal stabilizer, and consequent loss of controllability of the airplane.

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\n0 2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by removing Amendment 39-14833 (71 FR 68432, November 27, 2006) and by adding the following new airworthiness directive (AD): \n\n2011-14-02 The Boeing Company: Amendment 39-16737. Docket No. FAA- 2010-0033; Directorate Identifier 2009-NM-099-AD. \n\nEffective Date \n\n\n\t(a) This AD becomes effective November 16, 2011. \n\nAffected ADs \n\n\n\t(b) This AD supersedes AD 2006-24-04, Amendment 39-14833, (71 FR 68432, November 27, 2006). \n\nApplicability \n\n\n\t(c) This AD applies to all The Boeing Company Model 767-200, - 300, -300F, and -400ER series airplanes, certificated in any category. \n\n((Page 63175)) \n\nSubject \n\n\n\t(d) Air Transport Association (ATA) of America Code 53: Fuselage. \n\nUnsafe Condition \n\n\n\t(e) This AD results from reported fatigue cracking in the vertical inner chord and the forward outer chord while doing the detailed inspection of the horizontal inner chord at STA 1809.5. The Federal Aviation Administration is issuing this AD to detect and correct fatigue cracking in the bulkhead structure at STA 1809.5 and the vertical inner chord at STA 1809.5, which could result in failure of the bulkhead structure for carrying the flight loads of the horizontal stabilizer, and consequent loss of controllability of the airplane. \n\nCompliance \n\n\n\t(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\nRestatement of Requirements of AD 2006-24-04 (71 FR 68432, November 27, 2006), With Updated Service Information \n\nRepetitive Inspectionsand Corrective Actions \n\n\n\t(g) Before the accumulation of 15,000 total flight cycles, or within 3,000 flight cycles after January 2, 2007 (the effective date of AD 2006-24-04 (71 FR 68432, November 27, 2006)), whichever is later: Do the detailed and high frequency eddy current (HFEC) inspections for cracking as specified in Parts 1, 2, 3, and 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 767- 53A0131, dated March 30, 2006; or Revision 1, dated March 12, 2009; and do all corrective actions before further flight; by accomplishing all the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006; or Revision 1, dated March 12, 2009; except as provided by paragraph (h) of this AD. After the effective date of this AD, use only Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009. Repeat the inspections thereafter at intervals not to exceed 6,000 flight cycles. Accomplishing the corrective action for the inspections specified in Part 1, 2, 3, or 4, as applicable, of Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006; or Revision 1, dated March 12, 2009; as applicable; terminates the repetitive inspections for that area only. \n\nExceptions to Service Bulletin \n\n\n\t(h) If any cracking is found in the skin or in any structure other than the forward outer chord, horizontal inner chord, or vertical inner chord during any inspection required by paragraph (g) or (k) of this AD, and Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006; or Revision 1, dated March 12, 2009; specifies to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (n) of this AD; except that repairing or replacing stringers in accordance with Subject 53-00- 03--Fuselage Stringers, of the applicable SRM identified in table 1 of this AD is an acceptable method ofcompliance for those specific actions required by this AD. \n\nOptional Terminating Action for the Repetitive Inspections Required by Paragraph (g) of This AD \n\n\n\t(i) For airplanes on which no cracking is found during the most recent detailed and HFEC inspections for a specified area as required by paragraph (g) of this AD: Paragraphs (i)(1) through (i)(5) of this AD provide optional terminating action for the repetitive inspections required by paragraph (g) of this AD for the specified area only. \n\t(1) Modification of a specified area in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, terminates the repetitive inspections required by paragraph (g) of this AD for that area only. \n\t(2) Modification of a forward outer chord in accordance with the procedures specified in paragraphs (i)(2)(i) through (i)(2)(v) of this AD, as applicable, terminates the repetitive inspections required by paragraph (g) of this AD for that area only.(i) For Model 767-200 series airplanes: Steps 4.A through 4.C and Steps 4.G through 4.P of Repair 9, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767- 200 Structural Repair Manual (SRM), Document D634T201. \n\t(ii) For Model 767-300 series airplanes: Steps 4.A through 4.C and Steps 4.G through 4.P of Repair 9, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767- 300 SRM, Document D634T210. \n\t(iii) For Model 767-300F series airplanes: Steps 4.A through 4.C and Steps 4.G through 4.P of Repair 9, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767- 300F SRM, Document D634T215. \n\t(iv) For Model 767-300BCF series airplanes: Steps 4.A through 4.C and Steps 4.G through 4.P of Repair 9, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767- 300BCF SRM, D634T235. \n\t(v) For Model 767-400 series airplanes: Steps 4.A through 4.C andSteps 4.G through 4.P of Repair 9, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767- 400 SRM, Document D634T225. \n\t(3) Modification of a forward outer chord in accordance with Steps 4.A through 4.C and 4.G through 4.P of Repair 9 of Subject 53- 80-08, Fuselage Bulkheads--Section 48, of the applicable SRM identified in table 1 of this AD also terminates the repetitive inspections required by paragraph (g) of this AD for that area. \n\t(4) Modification of a horizontal inner chord in accordance with the procedures specified in paragraphs (i)(4)(i) through (i)(4)(v) of this AD, as applicable, terminates the repetitive inspections required by paragraph (g) of this AD for that area. \n\t(i) For Model 767-200 series airplanes: Steps 4.A, 4.B, and 4.F through 4.P of Repair 10, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767-200 SRM, Document D634T201. \n\t(ii) For Model 767-300 series airplanes: Steps 4.A, 4.B, and 4.F through 4.P of Repair 10, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767-300 SRM, Document D634T210. \n\t(iii) For Model 767-300F series airplanes: Steps 4.A, 4.B, and 4.F through 4.P of Repair 10, dated April 15, 2006, of Subject 53- 80-08, Fuselage Bulkheads--Section 48, of the Boeing 767-300F SRM, Document D634T215. \n\t(iv) For Model 767-300BCF series airplanes: Steps 4.A, 4.B, and 4.F through 4.P of Repair 10, dated April 15, 2006, of Subject 53- 80-08, Fuselage Bulkheads--Section 48, of the Boeing 767-300BCF SRM, Document D634T235. \n\t(v) For Model 767-400 series airplanes: Steps 4.A, 4.B, and 4.F through 4.P of Repair 10, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767-400 SRM, Document D634T225. \n\t(5) Modification of a horizontal inner chord in accordance with Steps 4.A, 4.B, and 4.F through 4.P of Repair 10 of Subject 53-80- 08, Fuselage Bulkheads--Section 48, of the applicable SRM identified in Table 1 of this AD also terminates the repetitive inspections required by paragraph (g) of this AD for that area. \n\n\n\tTable 1--Revised SRMs ------------------------------------------------------------------------ \n\tSRM Revision Date ------------------------------------------------------------------------ Boeing 767-200 SRM, Document 105 December 15, 2010. \n\tD634T201. Boeing 767-300 SRM, Document 85 December 15, 2010. \n\tD634T210. Boeing 767-300F SRM, Document 49 December 15, 2010. \n\tD634T215. Boeing 767-300BCF SRM, 9 December 15, 2010. \n\tDocument D634T235. Boeing 767-400 SRM, Document 32 December 15, 2010. \n\tD634T225. ------------------------------------------------------------------------ \n\n\n\n\n\n((Page 63176)) \n\n\n\tNote 1: We have reformatted paragraph (i) of this AD to differentiate the methods of compliance specified in that paragraph. \n\nCredit for Previously Accomplished Repairs \n\n\n\t(j) Repair of a forward outer chord done before January 2, 2007, in accordance with Repair 9, dated April 15, 2006, of Subject 53-80- 08, Fuselage Bulkheads--Section 48, of the Boeing 767-200 SRM, Document D634T201; Boeing 767-300 SRM, Document D634T210; Boeing 767-300F SRM, Document D634T215; Boeing 767-300BCF SRM, D634T235; or Boeing 767-400 SRM, Document D634T225; as applicable; is acceptable for compliance with the requirements of paragraph (g) of this AD for that area only. Repair of a horizontal inner chord before January 2, 2007, in accordance with Repair 10, dated April 15, 2006, of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the Boeing 767-200 SRM, Document D634T201; Boeing 767-300 SRM, Document D634T210; Boeing 767-300F SRM, Document D634T215; Boeing 767-300BCF SRM, Document D634T235; or Boeing 767-400 SRM, Document D634T225; as applicable; is acceptable for compliance with the terminating requirements of paragraph (g) of this AD for that areaonly. \n\nNew Requirements of This AD \n\nInspections \n\n\n\t(k) At the later of the times specified in paragraphs (k)(1) and (k)(2) of this AD: Do the detailed and HFEC inspections for cracking as specified in Parts 5 and 6 of the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009; and do all applicable corrective actions by accomplishing all the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009; except as provided by paragraph (h) of this AD. Do all applicable corrective actions before further flight. Repeat the inspections thereafter at intervals not to exceed 6,000 flight cycles. Accomplishing the corrective action for the inspections specified in Part 5 or 6 of the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009, as applicable, terminates the repetitive inspections for that area only.(1) Before the accumulation of 15,000 total flight cycles or within 6,000 flight cycles after the inspection required by paragraph (g) of this AD, whichever occurs later. \n\t(2) Within 30 days after the effective date of this AD. \n\nOptional Terminating Action for the Repetitive Inspections Required by Paragraph (k) of This AD \n\n\n\t(l) For airplanes on which no cracking is found during the most recent detailed and HFEC inspections for a specified area, as required by paragraph (k) of this AD: Paragraphs (l)(1) and (l)(2) of this AD provide optional terminating action for the repetitive inspections required by paragraph (k) of this AD for that area only. After the effective date of this AD, only the applicable SRM identified in table 1 of this AD or a method approved by the Manager, Seattle ACO, may be used. \n\t(1) Modify the specified area in accordance with Steps 4.A through 4.C and 4.G through 4.Q of Repair 11 of Subject 53-80-08, Fuselage Bulkheads--Section 48, of the applicable SRM identified in table 1 or table 2 of this AD, except as provided by paragraph (m) of this AD. \n\t(2) Modify the specified area in accordance with a method approved by the Manager, Seattle ACO. \n\n\n\tTable 2--Previous SRMs ------------------------------------------------------------------------ \n\tSteps-- Dated-- Of-- ------------------------------------------------------------------------ 4.A through 4.C and 4.G August 15, 2008..... Boeing 767-200 SRM, \n\tthrough 4.Q of Repair 11 of Document D634T201. \n\tSubject 53-80-08. 4.A through 4.C and 4.G August 15, 2008..... Boeing 767-300 SRM, \n\tthrough 4.Q of Repair 11 of Document D634T210. \n\tSubject 53-80-08. 4.A through 4.C and 4.G August 15, 2008..... Boeing 767-300F SRM, \n\tthrough 4.Q of Repair 11 of Document D634T215. \n\tSubject 53-80-08. 4.A through 4.C and 4.G August 15, 2008..... Boeing 767-300BCF \n\tthrough 4.Q of Repair 11 of SRM, Document \n\tSubject 53-80-08. D634T235. 4.A through 4.C and 4.G August 15, 2008..... Boeing 767-400 SRM, \n\tthrough 4.Q of Repair 11 of Document D634T225. \n\tSubject 53-80-08. ------------------------------------------------------------------------ \n\n\n\n\n\tNote 2: We have reformatted paragraph (l) of this AD to differentiate the methods of compliance specified in that paragraph. \n\nException to SRM Modification Specified in Paragraph (l) of This AD \n\n\n\t(m) If, during accomplishment of any modification in accordance with paragraph (l) of this AD, any cracking is found and the applicable SRM referenced in paragraph (l) of this AD specifies to contact Boeing for appropriate action: Before further flight, repair the cracking in accordance with a method approved by the Manager, Seattle ACO. 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\nAlternative Methods of Compliance (AMOCs) \n\n\n\t(n)(1) The Manager, Seattle ACO, 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. Or, e-mail information 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 any repair 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 previously in accordance with AD 2006-24-04 (71 FR 68432, November 27, 2006) are approved as AMOCs for the corresponding provisions of this AD. \n\nMaterial Incorporated by Reference \n\n\n\t(o) You must use the service information specified in paragraph (o)(1) of this AD to do the actions required by this AD, unless the AD specifies otherwise. If you accomplish the optional actions specified by this AD, you must use the service information specified in paragraph (o)(2) of this AD to perform those actions, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference (IBR) under 5 U.S.C. 552(a) and 1 CFR part 51 of the following service information on November 16, 2011: \n\t(1) Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009. \n\t(2) Subject 53-00-03, Fuselage Stringers, of Chapter 53, Fuselage; or Subject 53-80-08, Fuselage Bulkheads--Section 48, Repair 9--Station 1809.5 Bulkhead--Forward Outer Chord Repair Between S-4 to S-8, Repair 10--Station 1809.5 Bulkhead--Horizontal Inner Chord Repair at Approximately WL 257 and BL 28, or Repair 11-- Station 1809.5 Bulkhead--Vertical Inner Chord Repair at Approximately WL 256 and BL 30, as applicable, of Chapter 53, Fuselage; as applicable; of the applicable Structural Repair Manual (SRM) specified in paragraphs (o)(2)(i) through (o)(2)(v) of this AD. \n\t(i) Boeing 767-200 SRM, Document D634T201, Revision 105, dated December 15, 2010. Only the transmittal letter, dated \n\n((Page 63177)) \n\nDecember 15, 2010, of this document contains the revision level of the document. \n\t(ii) Boeing 767-300 SRM, Document D634T210, Revision 85, dated December 15, 2010. Only page 1 of the transmittal letter, dated December 15, 2010, of this document contains the revision level of the document. \n\t(iii) Boeing 767-300F SRM, Document D634T215, Revision 49, dated December 15, 2010. Only page 1 of the transmittal letter, dated December 15, 2010, of this document contains the revision level of the document. \n\t(iv) Boeing 767-300BCF SRM, Document D634T235, Revision 9, dated December 15, 2010. Only page 1 of the transmittal letter, dated December 15, 2010, of this document contains the revision level of the document. \n\t(v) Boeing 767-400 SRM, Document D634T225, Revision 32, dated December 15, 2010. Only page 1 of the transmittal letter, dated December 15, 2010, of this document contains the revision level of the document. \n\t(3) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\t(4) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221. \n\t(5) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Discussion \n\n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that supersedes AD 2006-24-04, Amendment 39-14833 (71 FR 68432, November 27, 2006). The existing AD applies to all Model 767 airplanes. That NPRM was published in the Federal Register on February 8, 2010 (75 FR 6154). That NPRM proposed to continue to require repetitive detailed and HFEC inspections of the STA 1809.5 bulkhead for cracking, and corrective actions if necessary. That NPRM also proposed to expand the inspection area to include the vertical inner chord at STA 1809.5. \n\nComments \n\n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been received on the NPRM (75 FR 6154, February 8, 2010). \n\nSupport for the NPRM \n\n\n\tContinental Airlines (CAL) stated that it supports the intent of the NPRM (75 FR 6154, February 8, 2010). \n\nRequest To Revise Paragraph (k)(1) of the NPRM \n\n\n\tBoeing requested that we revise the compliance time in paragraph (k)(1) of the NPRM (75 FR 6154, February 8, 2010) to state "whichever occurs later'' rather than "whichever occurs first.'' Boeing stated that a similar AD, AD 2006-24-04 (71 FR 68432, November 27, 2006) (the AD being superseded), provides a choice of the later of two compliance times. Boeing stated that changing the compliance time language in paragraph (k)(1) of the NPRM would make this AD consistent with AD 2006-24-04. \n\tWe agree with the request for the reasons provided by the commenter, and we have revised paragraph (k)(1) of this final rule accordingly. \n\nRequest To Add Model 767-300BCF and 767-200SF Structural Repair Manuals (SRMs) To Clarify Terminating Action \n\n\n\tBoeing requested that we specify Model 767-300BCF and Model 767- 200SF SRMs in paragraphs (i) and (m) of the NPRM (75 FR 6154, February 8, 2010) to clarify the terminating action for converted Model 767-200 and -300 series airplanes. Boeing stated that some Model 767-300 airplanes have been converted to Model 767-300BCF airplanes, and some Model 767-200 airplanes have been converted to Model 767-200SF airplanes. Boeing stated that the Model 767-200SF and Model 767- \n\n((Page 63173)) \n\n300BCF SRMs differ from the Model 767-200 and Model 767-300 SRMs. \n\tWe partially agree with the request. The Model 767-300BCF is unique and has its own SRM documents. We have added the Model 767-300BCF SRMs to paragraphs (i) and (j) of this final rule and table 1 of this final rule (table 1 follows paragraph (l) of this final rule; paragraph (l) of this final rule was referred to as paragraph (m) in the NPRM (75 FR 6154, February 8, 2010)). \n\tHowever, the Boeing Model 767-200SF SRM does not include Subject 53-80-08, which is the subject referenced in paragraphs (i) and (l) of this AD; therefore, we have not changed the AD in regard to this model. The Model 767-200SF is unique and has its own SRM documents. After that material is developed, we will consider requests for approval of an alternative method of compliance (AMOC) under the provisions of paragraph (n) of this final rule. \n\nRequest To Clarify and Revise Paragraph (h) of the NPRM \n\n\n\tCAL requested that we clarify the AMOC requirements of paragraph (h) of the NPRM (75 FR 6154, February 8, 2010). CAL asserted that paragraph 3.B. of the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009, allows repair of the vertical inner chord in accordance with Repair 11 of Subject 53-80-08; therefore, the vertical inner chord needs to be added to paragraph (h) of the NPRM as an exclusion to the AMOC requirements. \n\tWe agree with commenter's request for the reasons provided. We have revised paragraph (h) of this AD to add the reference to the vertical inner chord, as requested by CAL. \n\tCAL also stated that for repairs or replacements of stringers and non-principal structural elements (PSE) parts (e.g., attach brackets, support clips, etc.), an AMOC should not be necessary. For instance, Parts 3 and 4 of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009, specify the detailed inspection of the structure surrounding the forward outer chord of the STA 1809.5 bulkhead, and the corresponding figures illustrate the inspection area, which encloses the stringers and attach fittings. As written, CAL stated that paragraph (h) of the NPRM (75 FR 6154, February 8, 2010) will prevent operators from making stringer repairs/replacements using "SRM 53-00- 03'' without first obtaining an AMOC. CAL stated further that replacing cracked clips and brackets using certain "Boeing drawings'' should not require an AMOC. \n\tCAL also requested that we revise paragraph (h) of the NPRM (75 FR 6154, February 8, 2010) to read as follows: "If any cracking is found in the skin or the STA 1809.5 bulkhead's principal structural elements (PSE) other than the forward outer chord, horizontal inner chord, and vertical inner chord during any inspection required by paragraph (g) or (k) of this AD, and Boeing Service Bulletin 767-53A0131, dated March 30, 2006; or Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009; specifies to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (n) of this AD. When replacing cracked parts per the Boeing drawings or repairing stringers per 767 SRM 53-00-03, approval in accordance with the procedures specified in paragraph (n) of this AD is not required.'' \n\tWe partially agree with the request to revise paragraph (h) of this final rule. In order for a method of compliance other than the method(s) provided by the AD to be used, that method must be approved under the provisions of paragraph (n) of this AD. It is crucial that the FAA and Boeing are aware of all repairs made to PSEs or surrounding structure, and that damage tolerance be performed on each repair to establish its effect on the fatigue life of the affected structure. \n\tIn addition, we have determined that repairing/replacing the stringers in accordance with the SRM referenced by the commenter is an acceptable method of compliance for those specific requirements of paragraph (h) of this AD. We have revised paragraph (h) of this AD accordingly. \n\tHowever, we disagree with including references to "Boeing drawings'' for replacing cracked clips and brackets. We must cite specific service information (with dates and revision levels) in our ADs and would need to have the applicable drawings submitted for review prior to including those drawings in an AD. Each operator may be using different Boeing drawings as reference for replacing cracked clips and brackets. In addition, we do not consider it appropriate to include various provisions in an AD applicable only to certain airplanes or to a single operator's unique use of an affected airplane. Individual operators may request approval of an AMOC, provided sufficient data are submitted to substantiate such a request. \n\nRequest To Clarify the Requirements of Paragraph (l) of the NPRM \n\n\n\tABX requested clarification as to why paragraph (l) of the NPRM (75 FR 6154, February 8, 2010) is included. ABX stated that the NPRM specifies the limits in each applicable paragraph, and that the NPRM does not refer to paragraph 1.E., "Compliance,'' of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009. ABX stated that the inclusion of paragraph (l) of the NPRM leads one to believe that somewhere in the NPRM other limits are hidden. \n\tWe agree to provide clarification. We have determined that paragraph (l) of the NPRM (75 FR 6154, February 8, 2010) was included unnecessarily because the NPRM did not refer to paragraph 1.E., "Compliance,'' of Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009. Therefore, we have removed thatparagraph and other references to it from this final rule. \n\nRequest To Revise Note 1 of the NPRM \n\n\n\tABX requested that we revise Note 1 of the NPRM (75 FR 6154, February 8, 2010) from "Guidance on modifying a vertical inner chord * \n* *'' to "Approved methods on modifying a vertical inner chord * * *''\nABX stated that Table 1 of the NPRM lists service information that provides guidance on modifying a vertical inner chord. ABX noted that this service information does not appear to be approved by the Manager of the Seattle Aircraft Certification Office (ACO). ABX stated that it believes that this service information should be approved for terminating action for the condition of no cracking found during the most recent detailed and HFEC inspections. ABX noted that the modification, with the removal of the damaged area, is approved as a terminating action when the cracks are found. ABX stated that it believes that the modification should also be approved when no cracks are found.We partially agree. We agree that accomplishing the terminating modification specified in Boeing Alert Service Bulletin 767-53A0131, Revision 1, dated March 12, 2009, terminates the applicable inspections for airplanes on which cracking is found and those on which cracking is not found. We have removed Note 1 of the NPRM (75 FR 6154, February 8, 2010) from the final rule and, instead, have revised paragraph (l) of the final rule to incorporate the information in Note 1 to specify that the optional terminating modification may also be done in \n\n((Page 63174)) \n\naccordance with the applicable Boeing 767 SRM. In addition, paragraph (m) of this final rule specifies that if any cracking is found during any modification done in accordance with paragraph (l) of this AD, and the applicable Boeing 767 SRM specifies to contact Boeing for appropriate action, the cracking must be repaired in accordance with a method approved by the Manager of the Seattle Aircraft Certification Office. We also note that the SRM is an FAA-approved document. \n\nExplanation of Additional Changes to This AD \n\n\n\tWe have added a new table 1 to this final rule to provide the applicable, current SRMs; we have re-identified subsequent tables accordingly. \n\tWe have changed paragraphs (i) and (l) of this final rule to specify specific steps of the applicable SRM identified in table 1 of this AD. We have also reformatted paragraphs (i) and (l) of this final rule to differentiate the methods of compliance, and added new Note 1 and Note 2 to this final rule to explain the reformatting changes. \n\tWe have revised the references to the SRM in the following locations to accurately identify Subject 53-80-08, Fuselage Bulkheads-- Section 48: Paragraphs (i)(2)(i) through (i)(2)(v), (i)(3), (i)(4)(i) through (i)(4)(v), (i)(5), (j), and (l)(1) of this AD. \n\nConclusion \n\n\n\tWe have carefully reviewed the available data, including the comments that have been received, and determined that air safety andthe public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nExplanation of Change to Costs of Compliance \n\n\n\tSince issuance of the NPRM (75 FR 6154, February 8, 2010), 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\n\tThere are about 975 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\n\tEstimated Costs -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\tNumber of \n\tWork AverageU.S.- \n\tAction hours labor rate Parts Cost per airplane registered Fleet cost \n\tper hour airplanes -------------------------------------------------------------------------------------------------------------------------------------------------------- Repetitive inspections of STA 1809.5 12 $85 None..................... $1,020 per inspection 354 $361,080 per inspection \n\t(required by AD 2006-24-04 (71 FR cycle. cycle. \n\t68432, November 27, 2006)). Inspection of inner chord (new action) 2 85 None..................... $170 per inspection cycle 354 $60,180 per inspection \n\tcycle. -------------------------------------------------------------------------------------------------------------------------------------------------------- \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\tWe have determined that this AD will not have federalism implications under ExecutiveOrder 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\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.