AD 2012-26-04

We are superseding an existing airworthiness directive (AD) for certain The Boeing Company Model 757-200, -200PF, and -200CB series airplanes powered by Rolls-Royce engines. That AD currently requires repetitive inspections of the shim installation between the drag brace fitting vertical flange and bulkhead, and repair if necessary; for certain airplanes, an inspection for cracking of the four critical fastener holes in the horizontal flange, and repair if necessary; and, for airplanes without conclusive records of previous inspections, performing the existing actions. This new AD reduces the repetitive inspection interval; adds repetitive detailed inspections for cracking of the bulkhead, and repair if necessary; allows an extension of the repetitive intervals for certain airplanes by also doing repetitive ultrasonic inspections for cracking of the bulkhead, and repair if necessary; and provides an option for a high frequency eddy current inspection for cracking of the critical fastener holes, and repair if necessary. This action also adds a terminating action for certain repetitive inspections. This AD was prompted by reports of loose fasteners and cracks at the joint common to the aft torque bulkhead and strut-to-diagonal brace fitting, and one report of such damage occurring less than 3,000 flight cycles after the last inspection. We are issuing this AD to detect and correct cracks, loose and broken bolts, and shim migration in the joint between the aft torque bulkhead and the strut-to-diagonal brace fitting, which could result in damage to the strut and consequent separation of the strut and engine from 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 FAA amends Sec. 39.13 by removing airworthiness directive (AD) 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008), and adding the following new AD: \n\n2012-26-04 The Boeing Company: Amendment 39-17299; Docket No. FAA- 2011-0724; Directorate Identifier 2010-NM-181-AD. \n\n(a) Effective Date \n\n\n\tThis airworthiness directive (AD) is effective February 22, 2013. \n\n(b) Affected ADs \n\n\n\tThis AD supersedes AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008). \n\n(c) Applicability \n\n\n\tThis AD applies to The Boeing Company Model 757-200, -200PF, and -200CB series airplanes; certificated in any category; line numbers1 through 1048 inclusive; powered by Rolls-Royce engines. \n\n(d) Subject \n\n\n\tJoint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 54, Nacelles/Pylons. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of loose fasteners and cracks at the joint common to the aft torque bulkhead and strut-to-diagonal brace fitting, and one report of such damage occurring less than 3,000 flight cycles after the last inspection. We are issuing this AD to detect and correct cracks, loose and broken bolts, and shim migration in the joint between the aft torque bulkhead and the strut-to-diagonal brace fitting, which could result in damage to the strut and consequent separation of the strut and engine from the airplane. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Retained One-Time Inspection and Repair With Optional Inspection Method \n\n\n\tThis paragraph restates the one-time inspection and repair required by paragraph (g) of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008), with optional inspection method and revised service information. For airplanes identified in paragraphs (g)(1) and (g)(2) of this AD: Within 90 days after August 24, 2007 (the effective date of AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007)), do a high frequency eddy current (HFEC) inspection for cracking of the four critical fastener holes in the horizontal flange and, before further flight, do all applicable repairs, in accordance with Part IV of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007; Boeing Alert Service \n\n((Page 4045)) \n\nBulletin 757-54A0047, Revision 4, dated June 24, 2010; or Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011; except as required by paragraph (i)(3) of this AD. As of the effective date of this AD, only Boeing Alert Service Bulletin 757- 54A0047, Revision 5, dated June 9, 2011, may be used to accomplish the actions required by this paragraph. Doing an ultrasonic inspection for cracking of the fasteners, in accordance with Part IV of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 4, dated June 24, 2010; or Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011; is an acceptable method of compliance with the HFEC inspection requirement of this paragraph. \n\t(1) Airplanes on which findings on the horizontal or vertical fasteners or the shims led to a rejection of any fastener during the actions specified in Boeing Alert Service Bulletin 757-54A0047, dated November 13, 2003; or Boeing Service Bulletin 757-54A0047, Revision 1, dated March 24, 2005. \n\t(2) Airplanes that had equivalent findings prior to the actions specified in Boeing Alert Service Bulletin 757-54A0047, dated November 13, 2003, except for findings on airplanes identified as Group 1, Configuration 2, in Boeing Alert Service Bulletin 757- 54A0047, Revision 3, dated June 27, 2007, that were prior to the incorporation of Boeing Service Bulletin 757-54-0035. \n\n(h) Retained Repetitive Inspection and Repair With Reduced Interval \n\n\n\tThis paragraph restates the repetitive inspections and repair required by paragraph (h) of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008), with reduced repetitive intervals and revised service information. At the applicable initial times specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007, except as required by paragraphs (i)(1) and (i)(2) of this AD: Do the inspections specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD, and, before further flight, do all the applicable related investigative actions and repairs, by doing all the actions specified in Parts I and II of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27,2007; or by doing all the actions specified in Part I, and in Step 2 of Part II, of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047 Revision 4, dated June 24, 2010, or Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, except as required by paragraph (i)(3) of this AD. As of the effective date of this AD, only Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, may be used to accomplish the actions required by this paragraph. Repeat the inspections required by this paragraph at the times specified in paragraph (h)(4) of this AD. \n\t(1) Do detailed inspections of the shim installations between the vertical flange and bulkhead to determine if there are signs of movement. \n\t(2) Do detailed inspections of the four fasteners in the vertical flange to determine if there are signs of movement or if there are gaps under the head or collar. \n\t(3) Do detailed inspections of the fasteners that hold the strut to the horizontal flange of the strut-to-diagonal brace fitting to determine if there are signs of movement or if there are gaps under the head or collar. \n\t(4) Repeat the inspections required by paragraph (h) of this AD at the earlier of the times specified in paragraphs (h)(4)(i) and (h)(4)(ii) of this AD. Thereafter, repeat the inspections at intervals not to exceed the applicable intervals specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. \n\t(i) At intervals not to exceed the applicable intervals specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007. \n\t(ii) At intervals not to exceed the applicable intervals specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, or within 90 days after the effective date of this AD, whichever occurs later. \n\n(i) Retained Exceptions To Alert ServiceBulletin Procedures \n\n\n\tThis paragraph restates the exceptions to alert service bulletin procedures specified in paragraphs (i), (j), and (k) of AD 2008-05- 10, Amendment 39-15404 (73 FR 11347, March 3, 2008), with revised service information. \n\t(1) Where Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007, specifies a compliance time relative to ''the date on this service bulletin,'' this AD requires compliance within the corresponding specified time relative to the effective date of AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007). \n\t(2) Where Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007, specifies a compliance time relative to the ''date of issuance of airworthiness certificate,'' this AD requires compliance within the corresponding time relative to the date of issuance of the original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness. \n\t(3) If anycrack is found during any inspection required by this AD, and Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007; Boeing Alert Service Bulletin 757-54A0047, Revision 4, dated June 24, 2010; or Boeing Alert Service Bulletin 757- 54A0047, Revision 5, dated June 9, 2011; specifies to contact Boeing for appropriate action: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (q) of this AD. \n\n(j) Retained Inspection/Repair for Airplanes for Which There Are No Conclusive Inspection Records \n\n\n\tThis paragraph restates the inspection and repair requirements for airplanes for which there are no conclusive inspection records, as required by paragraph (l) of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008), with revised service information. For airplanes for which there are no conclusive records showing no loose or missing fasteners during previous inspections done in accordance with the requirements of AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007); or AD 2005-12-04, Amendment 39-14120 (70 FR 34313 June 14, 2005): Do the actions specified in paragraphs (j)(1) and (j)(2) of this AD, at the times specified in those paragraphs, as applicable. \n\t(1) Within 90 days after March 18, 2008 (the effective date of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008)), do the actions specified in paragraph (g) of this AD, except as required by paragraph (i)(3) of this AD. \n\t(2) At the applicable initial times specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007, do the actions specified in paragraph (h) of this AD, except as required by paragraphs (i)(2) and (k) of this AD. And, before further flight, do all applicable related investigative actions and repairs, by doing all the actions specified in Parts I and II of the Accomplishment Instructions of Boeing Alert Service Bulletin757-54A0047, Revision 3, dated June 27, 2007; or in Part 1 and in Step 2 of Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 757- 54A0047, Revision 4, dated June 24, 2010, or Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011; except as required by paragraph (i)(3) of this AD. As of the effective date of this AD, only Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, may be used to accomplish the actions required by this paragraph. Repeat the actions specified in paragraph (h) of this AD at the times specified in paragraph (h)(4) of this AD. \n\n(k) Retained Additional Exception To Alert Service Bulletin Procedures \n\n\n\tThis paragraph restates the exception to alert service bulletin procedures required by paragraph (m) of AD 2008-05-10, Amendment 39- 15404 (73 FR 11347, March 3, 2008). Where Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007, specifies a compliance time relative to ''the date on this service bulletin,'' this AD requires compliance within the corresponding specified time relative to March 18, 2008 (the effective date of AD 2008-05-10). \n\n(l) Retained Acceptable Method of Compliance with Certain Requirements of AD 2004-12-07, Amendment 39-13666 (69 FR 33561 June 16, 2004) \n\n\n\tThis paragraph restates an acceptable method of compliance with certain requirements of AD 2004-12-07, Amendment 39-13666 (69 FR 33561 June 16, 2004), specified by paragraph (p) of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008). Accomplishing the actions specified in paragraphs (g) and (h) of this AD terminates the requirements specified in paragraphs (b) and (d) of AD 2004-12- 07. \n\n((Page 4046)) \n\n(m) New Repetitive Inspections and Repair \n\n\n\tAt the applicable initial compliance times specified in paragraph (n) of this AD: Do the applicable actions specified in paragraph (m)(1) or (m)(2) of this AD, in accordance with Step 3 of Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 4, dated June 24, 2010; or Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. If no cracking is found, repeat the inspections thereafter at intervals not to exceed the applicable intervals specified in paragraph 1.E., ''Compliance,'' of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. If any crack is found during any inspection required by this paragraph, before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (q) of this AD. \n\t(1) For Group 1, Configuration 1 airplanes identified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011: Do the actions specified in paragraph (m)(1)(i) or (m)(1)(ii) of this AD. \n\t(i) Do a detailed inspection for cracking of the bulkhead in the area around the access door cutout and around the critical fastenersin the horizontal flange. \n\t(ii) Do a detailed inspection for cracking of the bulkhead in the area around the access door cutout and around the critical fasteners in the horizontal flange, and do an ultrasonic inspection for cracking of the bulkhead around the fasteners in the horizontal flange. Doing the actions in this paragraph extends the repetitive intervals of the inspections required by paragraph (n) of this AD. \n\t(2) For Group 1, Configuration 2 airplanes; and Group 2 airplanes; identified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011: Do a detailed inspection for cracking of the bulkhead in the area around the access door cutout and around the critical fasteners in the horizontal flange. \n\n(n) New Compliance Times for Paragraph (m) of This AD \n\n\n\tAt the applicable times specified in paragraphs (n)(1) and (n)(2) of this AD, do the actions required by paragraph (m) of this AD. \n\t(1) For Group 1, Configuration 1 airplanes identified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011: At the later of the times specified in paragraph (n)(1)(i) or (n)(1)(ii) of this AD. \n\t(i) Within 1,800 flight cycles after accomplishing the most recent inspection required by paragraph (h) or (j) of this AD. \n\t(ii) Within 90 days after the effective date of this AD. \n\t(2) For Group 1, Configuration 2 airplanes; and Group 2 airplanes; identified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011: At the later of the times specified in paragraph (n)(2)(i) or (n)(2)(ii) of this AD. \n\t(i) Within 3,000 flight cycles after accomplishing the most recent inspection required by paragraph (h) or (j) of this AD. \n\t(ii) Within 90 days after the effective date of this AD. \n\n(o) New Terminating Action for Certain Airplanes: Fastener Replacement \n\n\n\tFor Group 1, Configuration 2 airplanes; and Group 2 airplanes; as identified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June9, 2011: Within 9,000 flight cycles or 54 months after the effective date of this AD, whichever occurs first, replace the horizontal and vertical flange fasteners in the strut-to-diagonal brace fitting on the number 1 and number 2 struts with new fasteners, and do all related investigative and applicable corrective actions, in accordance with PART V of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, except where Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, specifies to contact Boeing for repair instructions, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (q) of this AD. Do all related investigative and corrective actions before further flight. Accomplishment of the actions required in paragraph (o) of this AD terminates the inspection requirements of paragraphs (g), (h), (j), and (m) of this AD for Group 1, Configuration 2 airplanes; and Group 2 airplanes; as identified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. \n\n(p) Credit for Previous Actions \n\n\n\t(1) Except for the actions specified in paragraphs (j), (m), and (o) of this AD, this paragraph provides credit for the actions required by paragraphs (g) and (h) of this AD, if those actions were performed before March 18, 2008 (the effective date of AD 2008-05- 10, Amendment 39-15404 (73 FR 11347, March 3, 2008), using Boeing Service Bulletin 757-54A0047, Revision 1, dated March 24, 2005; or Boeing Alert Service Bulletin 757-54A0047, Revision 2, dated January 31, 2007 (which are not incorporated by reference in this AD). \n\t(2) This paragraph provides credit for the initial inspection required by paragraph (h) of this AD, if that inspection was performed before June 29, 2005 (the effective date of AD 2005-12-04, Amendment 39-14120 (70 FR 34313, June 14, 2005)), using the actions required by paragraph (b) or (d), as applicable,of AD 2004-12-07, Amendment 39-13666 (69 FR 33561, June 16, 2004). \n\n(q) 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 any repair required by this AD if it is approvedby 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 2004-12-07, Amendment 39-13666 (69 FR 33561, June 16, 2004), are approved as AMOCs for the corresponding provisions of this AD. \n\t(5) AMOCs approved previously in accordance with AD 2005-12-04, Amendment 39-14120 (70 FR 34313, June 14, 2005), are approved as AMOCs for the corresponding provisions of this AD. \n\t(6) AMOCs approved previously in accordance with AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007), are approved as AMOCs for the corresponding provisions of this AD. \n\t(7) AMOCs approved previously in accordance with AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008), are approved as AMOCs forthe corresponding provisions of this AD. \n\n(r) Related Information \n\n\n\t(1) For more information about this AD, Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, Seattle Aircraft Certification Office (ACO), FAA, 1601 Lind Avenue SW., Renton, Washington 98057- 3356; phone: 425-917-6440; fax: 425-917-6590; email: Nancy.Marsh@faa.gov. \n\t(2) For Boeing 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; phone: 206-544-5000, extension 1; fax: 206-766-5680; Internet: https://www.myboeingfleet.com. \n\n(s) 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 February 22, 2013. \n\t(i) Boeing Alert Service Bulletin 757-54A0047, Revision 4, dated June 24, 2010. \n\t(ii) Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. \n\t(4) The following service information was approved for IBR on August 24, 2007, (72 FR 44753, August 9, 2007). \n\t(i) Boeing Alert Service Bulletin 757-54A0047, Revision 3, dated June 27, 2007. \n\t(ii) Reserved. \n\t(5) For Boeing 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; phone: 206-544-5000, extension 1; fax: 206-766-5680; Internet: https://www.myboeingfleet.com. \n\n((Page 4047)) \n\n\n\t(6) You may view this service information at 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(7) You may view this 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/cfr/ibr-locations.html.

Discussion \n\n\n\tWe issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 to supersede airworthiness directive (AD) 2008-05- 10, Amendment 39-15404 (73 FR 11347, March 3, 2008). (AD 2008-05-10 superseded AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007); and AD 2007-16-13 superseded AD 2005-12-04, Amendment 39-14120 (70 FR 34313, June 14, 2005).) AD 2008-05-10 applies to the specified products. The SNPRM published in the Federal Register on June 21, 2012 (77 FR 37332). The original NPRM (76 FR 52901, August 24, 2011) proposed to continue to require repetitive inspections of the shim installation between the engine strut vertical flange and bulkhead, and repair if necessary. That NPRM also proposed to continue to require, for certain airplanes, inspecting for cracking of the four critical fastener holes in the horizontal flange, and repair if necessary; and, for airplanes without conclusive records of previous inspections, performing the existing actions. Additionally, that NPRM proposed to reduce the repetitive inspection interval, add repetitive detailed inspections for cracking of the bulkhead, and repair if necessary; extend the repetitive intervals for certain airplanes by also doing repetitive ultrasonic inspections for cracking of the bulkhead, and repair if necessary; and add an option for a high frequency eddy current inspection for cracking of the critical fastener holes, and repair if necessary. The SNPRM proposed to add a terminating action for certain repetitive inspections. \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 37332, June 21, 2012) and the FAA's response to each comment. \n\n((Page 4043)) \n\nSupport for the SNPRM (77 FR 37332, June 21, 2012) \n\n\n\tUnited Airlines (United) stated that it has 41 Model 757-200 airplanes affected by the SNPRM (77 FR 37332, June 21, 2012). United stated that, in general, it concurs with the SNPRM to mandate the inspections and modifications described in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. \n\tUPS stated that it concurs with the reduced inspection interval specified in the SNPRM (77 FR 37332, June 21, 2012), as it provides additional opportunity beyond that required by AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008), to find and correct any damage. \n\nRequest To Change Compliance Time \n\n\n\tUnited requested that we remove the 54-month compliance time in favor of only a 9,000 airplane-cycle limit for the modification specified in paragraph (o) of the SNPRM (77 FR 37332, June 21, 2012). United stated that the 54-month compliance time does not align with current 72-month heavy check intervals at United. United stated that it understands the related bulkhead cracking to be a fatigue related failure, thus negating the need for a calendar driven modification limit. United stated it believes that the currently mandated repetitive inspection limits, in conjunction with a 9,000-airplane-cycle mandated modification limit only, would provide a safe program that would allow for a controlled implementation that minimizes the negative financial impact to operators. \n\tWe disagree with the request to change the specified compliance time. We have determined that the 54-month compliance time (grace period), as specified in Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011, is necessary to adequately address the identified unsafe condition. This structure has been the subject of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008); which superseded AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007); which superseded AD 2005-12-04, Amendment 39-14120 (70 FR 34313, June 14, 2005). In each of these ADs, the results from the new inspection found more damage than anticipated, and more frequent and complicated inspections were needed. \n\tIn developing an appropriate compliance time for the modification specified in paragraph (o) of this AD, we considered the safety implications, the time necessary to design an acceptable modification, and normal maintenance schedules for timely accomplishment of the modification. In light of these items, we have determined that a 54- month compliance time (grace period) is appropriate. However, under the provisions of paragraph (q) of this AD, we will consider requests for approval of an extension of the compliance time if sufficient data are submitted to substantiate that the extension would provide an acceptable level of safety. We have not changed the AD in this regard. \n\nRequest To Change Terminating Action \n\n\n\tUPS requested that the terminating action proposed in the SNPRM (77 FR 37332, June 21, 2012) be optional in lieu of continued reduced interval inspections, and the terminating action be required only if the reduced interval inspections find cracks or other damage at the fitting. \n\tWe do not agree to change the required terminating action specified in this AD because this portion of the Model 757 pylon has been the subject of AD 2008-05-10, Amendment 39-15404 (73 FR 11347, March 3, 2008); which superseded AD 2007-16-13, Amendment 39-15152 (72 FR 44753, August 9, 2007); which superseded AD 2005-12-04, Amendment 39-14120 (70 FR 34313, June 14, 2005). In each of these ADs, results from the new, more frequent, and more complicated inspections showed more damage than anticipated. Under the provisions of paragraph (q) of this AD, we will consider requests for approval of alternative methods of compliance (AMOC) if sufficient data are submitted to substantiate that continued inspections without the terminating action can mitigate the identified unsafe condition. We have not changed the AD in this regard. \n\nRequest To Specify Certain Section of Service Information \n\n\n\tBoeing requested that we specifically call out Part V of the Accomplishment Instructions of Boeing Alert Service Bulletin 757- 54A0047, Revision 5, dated June 9, 2011, in paragraph (o) of the SNPRM (77 FR 37332, June 21, 2012) to prevent misinterpretation in that paragraph because it is different than all other locations in the SNPRM. \n\tWe agree to specify Part V in paragraph (o) of this AD, as requested by Boeing, since doing so will help prevent misinterpretation. We have changed paragraph (o) of this AD to specify PART V of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-54A0047, Revision 5, dated June 9, 2011. \n\nRequest To Change Paragraph Header \n\n\n\tBoeing requested that we revise the header of paragraph (g) of the SNPRM (77 FR 37332, June 21, 2012), by deleting ''With Reduced Repetitive Intervals and New Optional Inspection Method.'' Boeing stated that there are no repetitive inspection requirements in paragraph (g) of the SNPRM. \n\tWe agree to modify the specified header, since the repetitive inspection is specified in paragraph (h) of this AD. We have removed the words ''Reduced Repetitive Intervals and New Optional Inspection Interval'' from the header of paragraph (g) 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--and minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the SNPRM (77 FR 37332, June 21, 2012) for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the SNPRM (77 FR 37332, June 21, 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 309 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD:Estimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Part I inspection on fasteners 28 work-hours x $85 $0 $2,380 per $735,420 per \n\tand shims--vertical flange per hour = $2,380 inspection cycle. inspection cycle. \n\t(retained actions from AD 2008- per inspection \n\t05-10, Amendment 39-15404 (73 FR cycle. \n\t11347, March 3, 2008)). \n\n((Page 4044)) \n\n\n\nPart II inspection on fasteners-- 6 work-hours x $85 0 $510 per inspection $157,590 per \n\thorizontal flange (retained per hour = $510 cycle. inspection cycle. \n\tactions from AD 2008-05-10, per inspectionAmendment 39-15404 (73 FR 11347, cycle. \n\tMarch 3, 2008)). Part IV inspection on critical 6 work-hours x $85 0 $510 per inspection $157,590 per \n\tfasteners--horizontal flange per hour = $510 cycle. inspection cycle. \n\t(retained action from AD 2008-05- per inspection \n\t10, Amendment 39-15404 (73 FR cycle. \n\t11347, March 3, 2008)). Part II additional inspection on 10 work-hours x $85 0 $850 per inspection $262,650 per \n\tfasteners--horizontal flange per hour = $850 cycle. inspection cycle. \n\t(new action). per inspection \n\tcycle. Part IV inspection on critical 8 to 22 work-hours 0 $680 to $1,870 per $210,120 to \n\tfasteners--horizontal flange x $85 per hour = inspection cycle. $577,830 per \n\t(new action). $680 to $1,870 perinspection cycle. \n\tinspection cycle. Part V fastener replacement Up to 37 work-hours 750 Up to $3,895 per Up to $1,203,555 \n\tflange (new action). x $85 per hour = strut. per strut. \n\t$3,145 per strut. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD. \n\nAuthority for This Rulemaking \n\n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, ''General requirements.'' Under thatsection, 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 Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.