AD 2018-04-06

We are superseding Airworthiness Directive (AD) 2012-12-05, which applied to all The Boeing Company Model 737-100, -200, -200C, - 300, -400, and -500 series airplanes. AD 2012-12-05 required repetitive inspections for cracking under the stop fittings and intercostal flanges and for cracking of the intercostal web, attachment clips, stringer splice channels, frame, reinforcement angle, shear web, frame outer chord and inner chord; a one-time inspection to detect missing fasteners; repetitive inspections of the cargo barrier net fitting for cracking; repetitive inspections for cracking of the stringer S-15L aft intercostal; and repair or corrective action if necessary. For certain airplanes, this AD adds new repetitive inspections of certain areas of the frame inner chord, and applicable on-condition actions. This AD was prompted by reports of additional cracking in locations not covered by the inspections in AD 2012-12-05. We are issuing this AD to address the unsafe conditionon these products.

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) 2012-12-05, Amendment 39-17084 (77 FR 36139, June 18, 2012), and adding the following new AD: \n\n2018-04-06 The Boeing Company: Amendment 39-19201; Docket No. FAA- 2017-0774; Product Identifier 2017-NM-036-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective March 30, 2018. \n\n(b) Affected ADs \n\n\n\tThis AD replaces AD 2012-12-05, Amendment 39-17084 (77 FR 36139, June 18, 2012) (''AD 2012-12-05''). \n\n(c) Applicability \n\n\n\t(1) This AD applies to all The Boeing Company Model 737-100, - 200, -200C, -300, -400, and -500 series airplanes, certificated in any category.(2) Installation of Supplemental Type Certificate (STC) ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/ rgstc.nsf/0/ebd1cec7b301293e86257cb30045557a/$FILE/ST01219SE.pdf) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a ''change in product'' alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17. \n\n(d) Subject \n\n\n\tAir Transport Association (ATA) of America Code 53, Fuselage. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of cracking of the station (STA) 348.2 frame above the two outboard fasteners attaching the frame inner chord and door stop fittings, and in the outboard chord at stringer S-16L; missing fasteners in the STA 348.2 frame inner chord; and additional cracking in locations not covered by the inspections in AD 2012-12-05. We are issuing this AD to detect and correct fatigue crackingof the intercostals on the forward and aft sides of the forward entry door cutout, which could result in loss of the forward entry door and rapid decompression of 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 Initial Compliance Time for Model 737-100, -200, -200C, - 300, -400, and -500 Series Airplanes, With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (i) of AD 2012-12-05, with no changes. For all Model 737-100, -200, -200C, - 300, -400, and -500 series airplanes, as identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after November 1, 2005 (the effective date of AD 2005-20-03, Amendment 39-14296 (70 FR 56361, September 27, 2005) (''AD 2005-20-03'')), whichever occurs later: Do the inspections required by paragraphs (i) and (j) of this AD. \n\n(h)Retained Initial Compliance Time for Model 737-200C Series Airplanes, With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (j) of AD 2012-12-05, with no changes. For all Model 737-200C series airplanes, as identified in Boeing Alert Service Bulletin 737- 53A1204, Revision 1, dated March 26, 2007: Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after September 9, 2009 (the effective date of AD 2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009) (''AD 2009-16-14'')), whichever occurs later, do the inspection required by paragraph (k) of this AD. \n\n(i) Retained Initial Inspection for Group 1 Configuration Airplanes, With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (k) of AD 2012-12-05, with no changes. For Group 1 airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Perform a \n\n((Page 7967)) \n\ndetailed inspection for cracking of the intercostal web, attachment clips, and stringer splice channels; and a high frequency eddy current (HFEC) inspection for cracking of the stringer splice channels located forward and aft of the forward entry door; and do all applicable corrective actions before further flight; in accordance with Parts 1 and 2 of the Work Instructions of Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003, or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or in accordance with Parts 1, 2, 4, and 5 of the Work Instructions of Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010. After September 9, 2009 (the effective date of AD 2009-16-14), and until July 23, 2012 (the effective date of AD 2012-12-05), Boeing Alert Service Bulletin 737- 53A1204, Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010; may be used to accomplish the actions required by this paragraph. As of July 23,2012, only Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, may be used to accomplish the actions required by this paragraph. \n\n(j) Retained Initial Inspection for Cargo Configuration Airplanes (Forward of the Forward Entry Door), With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (l) of AD 2012-12-05, with no changes. For Group 2 cargo airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Perform a detailed inspection for cracking of the intercostal webs and attachment clips located forward of the forward entry door, and do all applicable corrective actions before further flight, in accordance with Part 3 of the Work Instructions of Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003, or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or in accordance with Part 3 of Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010. After September 9, 2009 (the effective date of AD 2009-16-14), and until July 23, 2012 (the effective date of AD 2012-12-05), Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010; may be used to accomplish the actions required by this paragraph. As of July 23, 2012, only Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, may be used to accomplish the actions required by this paragraph. \n\n(k) Retained Initial Inspection for Cargo Configuration Airplanes (Aft of the Forward Entry Door), With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (m) of AD 2012-12-05, with no changes. For Group 2 cargo airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Perform a detailed inspection for cracking of the intercostal webs and attachment clips located aft of the forward entry door, and do allapplicable corrective actions before further flight, in accordance with Part 4 of the Work Instructions of Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or in accordance with Part 3 of Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010. As of July 23, 2012 (the effective date of AD 2012-12-05), only Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, may be used to accomplish the actions required by this paragraph. \n\n(l) Retained Repetitive Inspections, With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (n) of AD 2012-12-05, with no changes. Repeat the inspections required by paragraphs (i), (j), and (k) of this AD thereafter at intervals not to exceed 6,000 flight cycles after the previous inspection, or within 3,000 flight cycles after September 9, 2009, whichever occurs later. \n\n(m) Retained Exceptions to Boeing Alert Service Bulletin 737-53-1204, With No Changes \n\n\n\tThisparagraph restates the requirements of paragraph (o) of AD 2012-12-05, with no changes. Do the actions required by paragraphs (g), (h), (i), (j), (k), and (l) of this AD by accomplishing all the applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010; except as provided by paragraphs (m)(1) and (m)(2) of this AD. After September 9, 2009 (the effective date of AD 2009-16-14), and until July 23, 2012 (the effective date of AD 2012-12-05), Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010; may be used to accomplish the actions required by this paragraph. As of July 23, 2012, only Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24,2010, may be used to accomplish the actions required by this paragraph. \n\t(1) Where Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010; specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (s) of this AD. \n\t(2) Where Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; specifies a compliance time relative to the date of a service bulletin, this AD requires compliance relative to September 9, 2009 (the effective date of AD 2009-16-14). Where Boeing Special Attention Service Bulletin 737-53- 1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737- 53A1204, Revision 1, dated March 26, 2007;specifies a compliance time relative to the date of the initial release of a service bulletin, this AD requires compliance relative to November 1, 2005 (the effective date of AD 2005-20-03). \n\n(n) Retained Exceptions to Boeing Alert Service Bulletin 737-53A1204, Revision 2, Dated June 24, 2010, With No Changes \n\n\n\tThis paragraph restates exceptions to Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, specified in paragraph (r) of AD 2012-12-05, with no changes. \n\t(1) The access and restoration instructions identified in the Work Instructions of Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, are not required by this AD. Operators may perform those actions in accordance with approved maintenance procedures. \n\t(2) The use of Boeing Drawing 65-88700 is not allowed when accomplishing the actions required by this AD in accordance with the Work Instructions of Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010. \n\n(o) Retained Initial and Repetitive Inspections of the S-15L Aft Intercostal and Cargo Barrier Net Fitting for Model 737-200C Series Airplanes, With No Changes \n\n\n\tThis paragraph restates the requirements of paragraph (s) of AD 2012-12-05, with no changes. For Group 2 airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010: Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after July 23, 2012 (the effective date of AD 2012-12-05), whichever occurs later, do initial detailed and HFEC inspections for cracking of the S-15L aft intercostal between body station (BS) 348.2 and BS 360, and do a detailed inspection of the cargo barrier net fitting at the intercostal, in accordance with Figure 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010. If any cracking is found, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (s) of this AD. Repeat the inspections thereafter at intervals not to exceed 6,000 flight cycles. \n\n(p) Actions for Boeing Alert Service Bulletin 737-53A1240, Revision 2, Dated November 2, 2016, Including New Repetitive Inspections of Certain Fastener Holes \n\n\n\t(1) For airplanes identified as Group 1 and Group 3 in Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016: Except as required by paragraph (q) of this AD, at the applicable times specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016, do all applicable actions identified as ''RC'' (required for compliance) in, and in accordance with, the Accomplishment Instructions of Boeing Alert Service Bulletin 737- 53A1240, Revision 2, dated November 2, 2016. \n\t(2) For airplanes identified as Group 2 in Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016: Within 120 days after the effective date of this AD, do actions to correct the unsafe condition using a method approved in accordance with \n\n((Page 7968)) \n\nthe procedures specified in paragraph (s) of this AD. \n\n(q) Exceptions to Service Information Specifications \n\n\n\t(1) Where Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016, uses the phrase ''after the Revision 2 date of this service bulletin,'' for purposes of determining compliance with the requirements of this AD, the phrase ''after the effective date of this AD'' must be used. \n\t(2) Where Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016, specifies contacting Boeing, and specifies that action as RC: This AD requires using a method approved in accordance with the procedures specified in paragraph(s) of this AD. \n\n(r) Credit for Previous Actions \n\n\n\t(1) This paragraph provides credit for the actions specified in paragraphs (i), (j), and (m) of this AD, if those actions were performed before September 9, 2009 (the effective date of AD 2009- 16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009)), using Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003. \n\t(2) This paragraph provides credit for the actions specified in paragraph (p) of this AD, if those actions were performed before the effective date of this AD using Boeing Alert Service Bulletin 737- 53A1240, Revision 1, dated June 29, 2010, provided the conditions specified in paragraphs (r)(2)(i) and (r)(2)(ii) of this AD are met and except as provided by paragraph (r)(2)(iii) of this AD. Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, was incorporated by reference in AD 2012-12-05. \n\t(i) Note 1 of paragraph 3.A of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, was disregarded when accomplishing the actions. \n\t(ii) Boeing Drawing 65-88700 was not used when accomplishing the actions in accordance with the Work Instructions of Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010. \n\t(iii) The access and restoration instructions identified in the Work Instructions of Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, are not required. Operators are allowed to perform those actions in accordance with approved maintenance procedures. \n\n(s) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Los Angeles ACO Branch, 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 certification office, send it to the attention of the person identified in paragraph (t)(1) of this AD. Information may be emailed to: 9-ANM-LAACO-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, modification, or alteration required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Los Angeles ACO Branch, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\t(4) Except as required by paragraph (q)(2) of this AD: For service information that contains steps that are labeled as RC, the provisions of paragraphs (s)(4)(i) and (s)(4)(ii) of this AD apply. \n\t(i) The steps labeled as RC, including substeps under an RC step and any figures identified in an RC step, must be done to comply with the AD. If a step or substep is labeled ''RC Exempt,'' then the RC requirement is removed from that step or substep. An AMOC is required for any deviations to RC steps, including substeps and identified figures. \n\t(ii) Steps not labeled as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the RC steps, including substeps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition. \n\t(5) AMOCs approved previously for AD 2012-12-05 are approved as AMOCs for the corresponding provisions of paragraphs (g) through (o) of this AD. \n\t(6) AMOCs approved previously for AD 2012-12-05 are approved as AMOCs for the corresponding provisions of Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016, that are required by paragraph (p)(1) of this AD. \n\n(t) Related Information \n\n\n\t(1) Formore information about this AD, contact Galib Abumeri, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627- 5324; fax: 562-627-5210; email: galib.abumeri@faa.gov. \n\t(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (u)(6) and (u)(7) of this AD. \n\n(u) 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 March 30, 2018. \n\t(i) Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016. \n\t(ii) Reserved. \n\t(4) The following service information was approved for IBR on July 23, 2012 (77 FR 36139, June 18, 2012). \n\t(i) Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010. \n\t(ii) Reserved. \n\t(5) The following service information was approved for IBR on September 9, 2009 (74 FR 38901, August 5, 2009). \n\t(i) Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007. \n\t(ii) Reserved. \n\t(6) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740; telephone: 562-797-1717; internet: https://www.myboeingfleet.com. \n\t(7) You may view this service information at FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. \n\t(8) 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.

((Page 7965)) \n\nDiscussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2012-12-05, Amendment 39-17084 (77 FR 36139, June 18, 2012) (''AD 2012-12-05''). AD 2012-12-05 applied to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on August 15, 2017 (82 FR 38637). The NPRM was prompted by reports of additional cracking in locations not covered by the inspections in AD 2012-12-05. The NPRM proposed to continue to require repetitive inspections for cracking under the stop fittings and intercostal flanges and for cracking of the intercostal web, attachment clips, stringer splice channels, frame, reinforcement angle, shear web, frame outer chord and inner chord; a one-time inspection to detect missing fasteners; repetitive inspections of the cargo barrier net fitting for cracking; repetitive inspections for cracking of the stringer S-15L aft intercostal; and repair or corrective action if necessary. For certain airplanes, the NPRM also proposed to add new repetitive inspections of certain areas of the frame inner chord, and applicable on-condition actions. We are issuing this AD to detect and correct fatigue cracking of the intercostals on the forward and aft sides of the forward entry door cutout, which could result in loss of the forward entry door and rapid decompression of the airplane. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment. \n\nSupport for the NPRM \n\n\n\tThe Boeing Company supported the NPRM. \n\nEffect of Winglets on Accomplishing the Proposed Actions \n\n\n\tAviation Partners Boeing stated that accomplishing the Supplemental Type Certificate (STC) ST01219SE does not affect the actions specified in the NPRM. \n\tWe agree with the commenter. We have redesignated paragraph (c) of the proposed AD as paragraph (c)(1) of this AD and added paragraph (c)(2) to this AD to state that installation of STC ST01219SE does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a ''change in product'' alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17. \n\nRequest To Add AMOC Language \n\n\n\tSouthwest Airlines (SWA) asked that a note be added to paragraph (s) of the proposed AD to provide provisions for AMOCs previously approved for AD 2012-12-05. SWA stated that the language in paragraph (s) of the proposed AD does not account for AMOCs previously approved for AD 2012-12-05. \n\tWe agree with the commenter's request. We have added paragraphs (s)(5) and (s)(6) to this AD to include approval of AMOCs previously approved for AD 2012-12-05. \n\nChange to Final Rule \n\n\n\tWe have revised paragraph (r) of thisAD to provide credit for the actions specified in paragraphs (i), (j), and (m) of this AD, if those actions were performed before September 9, 2009 (the effective date of AD 2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009)), using Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003. \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously, and minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\tWe also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tWe reviewed Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016. The service information describes procedures for, among other actions, repetitive inspections of the fastener holes in the station (STA) 351.2 frame inner chord at stringer S-17L, and applicable on-condition actions. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 411 airplanes of U.S. registry. We estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Inspections for cracking under 18 work-hours x $85 $0 $1,530 per $628,830 per \n\tthe stop fittings and per hour = $1,530 inspection cycle. inspection cycle. \n\tintercostal flanges (retained per inspection \n\tactions from AD 2012-12-05) (411 cycle. \n\tairplanes). Inspection of areas forward of 2 work-hours x $85 0 $170 per inspection $69,870 per \n\tthe aft entry door (retained per hour = $170 cycle. inspection cycle. \n\tactions from AD 2012-12-05) (411 per inspection \n\tairplanes). cycle. Inspection of areas aft of the 1 work-hour x $85 0 $85 per inspection $34,935 per \n\tforward entry door (retained per hour = $85 per cycle. inspection cycle. \n\tactions from AD 2012-12-05) (411 inspection cycle. \n\tairplanes). Inspection for missing fasteners 1 work-hour x $85476 $561............... $230,571. \n\t(retained actions from AD 2012- per hour = $85. \n\t12-05) (411 airplanes). Inspection of fastener holes (new 27 work-hours x $85 0 $2,295 per $367,200 per \n\taction) (160 airplanes). per hour = $2,295 inspection cycle. inspection cycle. \n\tper inspection \n\tcycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe estimate the following costs to do any necessary repairs that are required based on the results of the inspections. We have no way of determining the number of aircraft that might need these repairs: \n\n((Page 7966)) \n\n\n\n\n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per \n\tAction Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Repair of cracking done in accordance with 24 work-hours x $85 per hour = $11,856 $13,896 \n\tBoeing Alert Service Bulletin 737-53A1240. $2,040. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that enables us to provide cost estimates for the other on-condition corrective 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 that section, Congress chargesthe 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\tThis AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division. \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.