Airworthiness Directives; The Boeing Company Airplanes, 2669-2674 [2012-859]

Download as PDF Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules me.boecom@boeing.com; Internet https:// www.myboeingfleet.com. For Air Cruisers service information identified in this AD, contact Air Cruisers Company, 1747 State Route 34, Wall, New Jersey 07727–3935; telephone: (732) 681–3527; fax: (732) 681– 9163; email: Aircruisers@zodiacaerospace.com. You may review copies of the referenced 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. Issued in Renton, Washington, on January 6, 2012. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2012–856 Filed 1–18–12; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2011–1419; Directorate Identifier 2010–NM–281–AD] RIN 2120–AA64 Airworthiness Directives; The Boeing Company Airplanes Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). AGENCY: We propose to supersede an existing airworthiness directive (AD) that applies to certain The Boeing Company Model 737–300, –400, and –500 series airplanes. The existing AD currently requires repetitive inspections for cracking of the crown area of the fuselage skin, and corrective actions if necessary. Since we issued that AD, we received additional reports of cracking at the horizontal chem-mill steps away from the lap joints over the entire crown area, and vertical chem-mill cracks adjacent to the butt joints. This proposed AD would add repetitive inspections for cracking using different inspection methods and would inspect additional areas, and corrective actions if necessary. This proposed AD would also require additional repairs to previously repaired areas and repetitive inspections for loose fasteners and replacement if necessary in certain previously repaired areas. This proposed AD would also reduce certain compliance times and extend certain other compliance times. We are proposing this AD to detect and correct fatigue cracking of the fuselage skin, which could cause the fuselage skin to EMCDONALD on DSK29S0YB1PROD with PROPOSALS SUMMARY: VerDate Mar<15>2010 14:58 Jan 18, 2012 Jkt 226001 fracture and fail, and result in rapid decompression of the airplane. DATES: We must receive comments on this proposed AD by March 5, 2012. ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments. • Fax: (202) 493–2251. • Mail: U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE., Washington, DC 20590. • Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. 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; email me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may review copies of the referenced 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. Examining the AD Docket You may examine the AD docket on the Internet at https:// www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (phone: (800) 647–5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt. FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM–120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 98057–3356; phone: (425) 917–6447; fax: (425) 917–6590; email: wayne.lockett@faa.gov. SUPPLEMENTARY INFORMATION: Comments Invited We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the PO 00000 Frm 00012 Fmt 4702 Sfmt 4702 2669 section. Include ‘‘Docket No. FAA–2011–1419; Directorate Identifier 2010–NM–281–AD’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments. We will post all comments we receive, without change, to https:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD. ADDRESSES Discussion On June 15, 2005, we issued AD 2005–13–27, amendment 39–14164 (70 FR 36821, June 27, 2005), for certain Boeing Model 737–300, –400, and –500 series airplanes. That AD requires repetitive inspections for cracking of the crown area of the fuselage skin, and corrective actions if necessary. That AD resulted from a Model 737 fuselage structure test and fatigue analysis that indicate fuselage skin cracking could occur between 21,000 and 42,000 total flight cycles. We issued that AD to detect and correct fatigue cracking of the fuselage skin, which could cause the fuselage skin to fracture and fail, and result in rapid decompression of the airplane. Actions Since Existing AD Was Issued Since we issued AD 2005–13–27, amendment 39–14164 (70 FR 36821, June 27, 2005), additional reports of cracking at the horizontal chem-mill steps away from the lap joints over the entire crown area, and vertical chemmill cracks adjacent to the butt joints, have been received. Although there were no changes to the applicability in AD 2005–13–17, we have changed paragraph (c) of the proposed AD to refer to Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Relevant Service Information We reviewed Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Boeing Special Attention Service Bulletin 737– 53–1234, Revision 1, dated March 31, 2005, was referred to for accomplishing the actions in AD 2005–13–27, amendment 39–14164 (70 FR 36821, June 27, 2005). Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, describes procedures for repetitive nondestructive inspections (NDI) (medium E:\FR\FM\19JAP1.SGM 19JAP1 EMCDONALD on DSK29S0YB1PROD with PROPOSALS 2670 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules frequency eddy current, magneto optical imaging, C-scan, or ultrasonic phased array) for cracking of the fuselage skin, and corrective actions if necessary. The NDI inspections for cracking of the skin include: • Inspecting for horizontal chem-mill cracking above the S–4 and S–10 lap joints • Inspecting for horizontal chem-mill cracking in the shear wrinkle areas • Inspecting for vertical chem-mill cracking at specified locations • Inspecting for horizontal chem-mill cracking in general pocket-to-pocket areas at specified locations. The corrective actions include installing a permanent repair (including related investigative actions and applicable corrective actions), installing a time-limited repair (including related investigative actions and applicable corrective actions), and contacting Boeing for repair instructions and doing the repair. For the temporary repair, the related investigative actions include a detailed inspection for cracks of the skin and a detailed inspection for corrosion and disbonding of the lap joint; and the corrective action is contacting Boeing for repair instructions and doing the repair. For the permanent repair, the related investigative actions include an NDI inspection for cracks of the skin and fastener holes and a detailed inspection for corrosion and disbonding of the skin; and the corrective action is contacting Boeing for repair instructions and doing the repair. Boeing Alert Service Bulletin 737– 53A1234, Revision 2, dated November 24, 2010, also describes procedures, for airplanes on which permanent repairs have already been done, for installing internal tear strap doublers. Boeing Alert Service Bulletin 737– 53A1234, Revision 2, dated November 24, 2010, also describes procedures, for airplanes on which time-limited repairs have already been installed, for doing repetitive detailed inspections for loose fasteners until the permanent repair is installed; and making the repair permanent (including related investigative actions and applicable corrective actions) by replacing the blind fasteners in the time-limited repair with solid rivets, and installing internal tear strap doublers. The related investigative actions include an NDI for cracks of the fastener holes and skin, a general visual inspection to determine if fasteners are installed common to the chem-milled steps, and a detailed inspection for corrosion and disbonding of the skin; and the corrective action is contacting Boeing for repair instructions and doing the repair. VerDate Mar<15>2010 14:58 Jan 18, 2012 Jkt 226001 The repetitive NDI inspection intervals vary depending on the configuration and the inspection option. Option 1 of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, specifies doing one of the following NDI; medium frequency eddy current inspection, magneto optical imaging inspection, or C-scan inspection). Option 2 specifies doing one NDI—an external ultrasonic phased array inspection. The repetitive interval ranges between 500 flight cycles and 2,400 flight cycles. Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, also specifies that if the inspection procedure is switched from Option 2 to Option 1, then the next Option 1 inspection must be done within the Option 2 interval; and that if the inspection procedure is switched from Option 1 to Option 2, then the next two Option 2 inspections must be done within the Option 1 interval. The inspection thresholds range from 25,000 total flight cycles to 81,000 total flight cycles, depending on the airplane configuration and inspection location. The grace periods range from 500 to 2,400 flight cycles or 1,800 flight hours, depending on the airplane configuration and inspection location. The repetitive inspection intervals range from 500 to 2,400 flight cycles, or 1,800 to 2,400 flight hours, depending on the inspection type and airplane configuration. For airplanes on which a time-limited repair is done, the compliance time to do the permanent repair is 6,000 flight cycles after doing the time-limited repair. Boeing Alert Service Bulletin 737– 53A1234, Revision 2, dated November 24, 2010, also includes an exception to inspecting the chem-mill steps under an existing external repair doubler, provided the conditions specified below apply: • The repair was installed after November 24, 2010 • The repair was approved by the FAA or by a Boeing Commercial Airplanes Organization Designation Authorization (ODA) who was authorized by the FAA to make such findings • The repair extends a minimum of three rows of fasteners on each side of the chem-mill step line in the circumferential direction, Or • The repair was approved by the FAA or by a Boeing Commercial Airplanes Organization Designation Authorization (ODA) who was authorized by the FAA to make such findings • The repair extends a minimum of 2 rows of 3⁄16 inch diameter fasteners on PO 00000 Frm 00013 Fmt 4702 Sfmt 4702 each side of the chem-mill step in the circumferential direction with 5–6D fastener spacing • The repair is similar to Figure 201, Repair 31 of Figure 201 of Subject 53– 00–01, ‘‘Fuselage Skin—General,’’ of the Boeing 737–300, 737–400, or 737–500 Structural Repair Manual, with regard to fastener type, size layout and pitch; repair part thickness and material; and repair installation. FAA’s Determination We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. Proposed AD Requirements This proposed AD would retain all of the requirements of AD 2005–13–27, Amendment 39–14164 (70 FR 36821, June 27, 2005). This proposed AD would add repetitive inspections for cracking using different inspection methods and would inspect additional areas, and corrective actions if necessary. This proposed AD would also require, for airplanes on which the existing permanent repair was done, installing internal tear strap doublers. This proposed AD would also require, for airplanes on which the existing temporary repair was done, doing repetitive inspections for loose fasteners and replacement if necessary, and installing a permanent repair. This proposed AD would also change (reducing some and extending others) initial compliance times and repetitive intervals. This proposed AD would also require accomplishing the actions specified in the service information described previously, except as discussed under ‘‘Differences Between the Proposed AD and the Service Information.’’ Differences Between the Proposed AD and the Service Information The Accomplishment Instructions in Boeing Alert Service Bulletin 737– 53A1234, Revision 2, dated November 24, 2010, do not provide a procedure for replacing loose fasteners; however, this proposed AD requires replacing any loose fastener with a new fastener of the same type and size as specified in Figures 6, 35 and 36, as applicable, of the Accomplishment Instructions of Boeing Alert Service Bulletin 737– 53A1234, Revision 2, dated November 24, 2010. Boeing Alert Service Bulletin 737– 53A1234, Revision 2, dated November 24, 2010, specifies to contact the manufacturer for instructions on how to E:\FR\FM\19JAP1.SGM 19JAP1 2671 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways: • In accordance with a method that we approve; or • Using data that meet the certification basis of the airplane, and that have been approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) whom we have authorized to make those findings. Costs of Compliance We estimate that this proposed AD affects 109 airplanes of U.S. registry. We estimate the following costs to comply with this proposed AD: ESTIMATED COSTS Cost on U.S. operators Action Labor cost Cost per product Inspection (retained actions from AD 2005– 13–27, Amendment 39-14164 (70 FR 36821, June 27, 2005). New NDI Inspections (medium frequency eddy current, magneto optical imaging, Cscan, or ultrasonic phased array). Install internal tear strap doublers (for airplanes on which permanent repair was already done). * Inspection for loose fasteners (for airplanes on which temporary repair was already done). * Install permanent repair (for airplanes on which temporary repair was already done). * Inspection adjacent to lap joint repair .......... 94 work-hours × $85 per hour = $7,990. $7,990 per inspection cycle ........... $870,910. Up to 390 work-hours × $85 per hour = $33,150. Up to $33,150 per inspection cycle Up to $3,613,350. Up to 30 work-hours × $85 per hour = $2,550. Up to $2,550 .................................. Up to $277,950. 1 work-hour × $85 per hour = $85 $85 ................................................. $9,265. Up to 48 work-hours × $85 per hour = $4,080. 3 work-hours × $85 per hour = $255. Up to $4,080 .................................. Up to $444,720. $255 ............................................... $27,795. * The cost for this action is for one typical repair only. We estimate the following costs to do any necessary repairs that would be required based on the results of the proposed inspection. We have no way of determining the number of aircraft that might need these repairs: ON-CONDITION COSTS Action Repair 1 ............................... 1 Repair Labor cost Parts cost 209 work-hours × $85 per hour = $17,765 Cost per product None ............................................................ $17,765. cost estimate is for one typical repair only. EMCDONALD on DSK29S0YB1PROD with PROPOSALS Authority for This Rulemaking Regulatory Findings List of Subjects in 14 CFR Part 39 Title 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. We 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. We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. For the reasons discussed above, I certify that the proposed regulation: (1) Is not a ‘‘significant regulatory action’’ under Executive Order 12866, (2) Is not a ‘‘significant rule’’ under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will not affect intrastate aviation in Alaska, and (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. Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. VerDate Mar<15>2010 14:58 Jan 18, 2012 Jkt 226001 PO 00000 Frm 00014 Fmt 4702 Sfmt 4702 The Proposed Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows: PART 39—AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by removing airworthiness directive (AD) 2005–13–27, Amendment 39–14164 (70 FR 36821, June 27, 2005), and adding the following new AD: The Boeing Company: Docket No. FAA– 2011–1419; Directorate Identifier 2010– NM–281–AD. E:\FR\FM\19JAP1.SGM 19JAP1 2672 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules (a) Comments Due Date The FAA must receive comments on this AD action by March 5, 2012. (b) Affected ADs This AD supersedes AD 2005–13–27, Amendment 39–14164 (70 FR 36821, June 27, 2005). (c) Applicability This AD applies to The Boeing Company Model 737–300, –400, and –500 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. (d) Subject Joint Aircraft System Component (JASC)/ Air Transport Association (ATA) of America Code 53, Fuselage. (e) Unsafe Condition This AD was prompted by reports of cracking at the horizontal chem-mill steps away from the lap joints over the entire crown area, and vertical chem-mill cracks adjacent to the butt joints. We are issuing this AD to detect and correct fatigue cracking of the fuselage skin, which could cause the fuselage skin to fracture and fail, and result in rapid decompression of the airplane. EMCDONALD on DSK29S0YB1PROD with PROPOSALS (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Restatement of Requirements of AD 2005– 13–27, Amendment 39–14164 (70 FR 36821, June 27, 2005): Initial Inspections per Boeing Special Attention Service Bulletin 737–53– 1234, Revision 1, Dated March 31, 2005 At the later of the times specified in paragraphs (g)(1) and (g)(2) of this AD, perform detailed and eddy current inspections for cracking of the crown area of the fuselage skin in accordance with Part 1, including the ‘‘Note,’’ of the Work Instructions of Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005, except as provided by paragraph (j) of this AD. Doing the inspections required by paragraph (m) of this AD terminates the inspections required by this paragraph for the corresponding inspection areas. (1) Before the accumulation of the applicable total flight cycles specified in the ‘‘Threshold’’ column of Table 1 of Figure 1 of Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005. (2) Within 4,500 flight cycles after August 1, 2005 (the effective date of AD 2005–13–27, Amendment 39–14164 (70 FR 36821, June 27, 2005). (h) Repetitive Inspections per Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, Dated March 31, 2005 Repeat either the detailed or eddy current inspections specified in paragraph (g) of this AD at the applicable intervals specified in paragraph (h)(1) or (h)(2) of this AD until paragraph (i)(1) or (i)(2) of this AD has been done, as applicable. Doing the inspection VerDate Mar<15>2010 14:58 Jan 18, 2012 Jkt 226001 required by paragraph (m) of this AD terminates the inspections required by this paragraph for the corresponding inspection area. (1) Repeat the detailed inspections thereafter at intervals not to exceed 1,200 flight cycles. (2) Repeat the eddy current inspections thereafter at intervals not to exceed 3,000 flight cycles. (k) No Reporting for Actions in Boeing Special Attention Service Bulletin 737–53– 1234, Revision 1, Dated March 31, 2005 Although Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005, specifies reporting certain information to Boeing, this AD does not require that action. (i) Permanent or Time-Limited Repair for Cracking Found During Inspections in Accordance With Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, Dated March 31, 2005 If any cracking is found during any inspection required by paragraph (g) or (h) of this AD, do the actions specified in paragraph (i)(1) or (i)(2) of this AD in accordance with Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005, except as provided by paragraphs (j) and (k) of this AD. (1) Before further flight, do a permanent repair (including related investigative actions and applicable corrective actions) in accordance with Part 2 of the Work Instructions of Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005. Doing a permanent repair ends the repetitive inspections required by paragraph (h) of this AD for the repaired area only. (2) Do the actions specified in paragraphs (i)(2)(i) and (i)(2)(ii) of this AD at the time specified in the applicable paragraph. Doing a time-limited repair ends the repetitive inspections required by paragraph (h) of this AD for the repaired area only. (i) Before further flight, do a time-limited repair (including related investigative actions and applicable corrective actions) in accordance with Part 3 of the Work Instructions of Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005. (ii) At the times specified in Figure 8 of Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005, do the related investigative and corrective actions in accordance with Part 3 of the Work Instructions of Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005. (l) Actions Accomplished According to Previous Issue of Service Bulletin Actions done before August 1, 2005, in accordance with Boeing Special Attention Service Bulletin 737–53–1234, dated June 13, 2002, are acceptable for compliance with the corresponding actions required by paragraphs (g), (h), and (i) of this AD. (m) New Requirements of This AD: Fuselage Skin Inspections at Chem-Mill Steps Common to Lap Joints Except as provided by paragraph (v)(1) of this AD; at the applicable time specified in Tables 1 and 2 of paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010: Do a non-destructive inspection (NDI) (medium frequency eddy current, magneto optical imaging, C-scan, or ultrasonic phased array) for horizontal chemmill cracking above the S–4 and S–10 lap joints, in accordance with paragraph 3.B.1.a. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, except as provided by paragraph (r) of this AD. Repeat the applicable inspections thereafter at intervals not to exceed those specified in paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Accomplishment of the inspections required by this paragraph terminates the requirements of paragraphs (g) and (h) of this AD for the corresponding inspection areas. Note 1: Option 1 of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, specifies doing one of the following NDI; medium frequency eddy current inspection, magneto optical imaging inspection, or C-scan inspection. Option 2 specifies doing one NDI—an external ultrasonic phased array inspection. These options have different compliance times after the initial inspection. (j) Contact the FAA Where Boeing Special Attention Service Bulletin 737–53–1234, Revision 1, dated March 31, 2005, specifies to contact Boeing for appropriate action: Before further flight, repair according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to data meeting the certification basis of the airplane approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings; or using a method approved in accordance with the procedures specified in paragraph (x) of this AD. For a repair method to be approved, the approval must specifically reference this AD. PO 00000 Frm 00015 Fmt 4702 Sfmt 4702 (n) Permanent or Time-Limited Repair for Cracking Found During Paragraph (m) Inspections If any cracking is found during any inspection required by paragraph (m) of this AD, do the actions specified in paragraph (n)(1) or (n)(2) of this AD. (1) Before further flight, do a permanent repair (including related investigative actions and applicable corrective actions) in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, except as provided by paragraph (v)(2) of this AD. Doing a permanent repair ends the repetitive inspections required by paragraph (m) of this AD for the repaired area only. (2) Do the actions specified in paragraphs (n)(2)(i), (n)(2)(ii), and (n)(2)(iii) of this AD at E:\FR\FM\19JAP1.SGM 19JAP1 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules the time specified in the applicable paragraph. Doing a time-limited repair ends the repetitive inspections required by paragraph (m) of this AD for the repaired area only. (i) Before further flight, do a time-limited repair (including related investigative actions and applicable corrective actions) in accordance with Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, except as provided by paragraph (v)(2) of this AD. (ii) Within 3,000 flight cycles after the time-limited repair was installed as specified in paragraph (n)(2)(i) of this AD or within 500 flight cycles after the effective date of this AD, whichever occurs later, do a detailed inspection for loose fasteners, in accordance with Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles until the permanent repair required by paragraph (n)(2)(iii) of this AD is done. If any loose fasteners are found, before further flight, replace the fasteners with new fasteners of the same type and size as specified in Figures 6, 35 and 36 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. (iii) Within 6,000 flight cycles after the time-limited repair was installed as specified in paragraph (n)(2)(i) of this AD, do the permanent repair specified in paragraph (n)(1) of this AD. EMCDONALD on DSK29S0YB1PROD with PROPOSALS (o) Fuselage Skin Inspections at Chem-mill Steps Common to Shear Wrinkle Areas Except as provided by paragraph (v)(1) of this AD; at the applicable time specified in Table 3 of paragraph 1.E, ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010: Do an NDI (medium frequency eddy current, magneto optical imaging, C-scan, or ultrasonic phased array) for horizontal chemmill cracking in the shear wrinkle areas, in accordance with paragraph 3.B.1.b of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Repeat the applicable inspections thereafter at intervals not to exceed those specified in paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. (p) Fuselage Skin Inspections at Specified Vertical Chem-mill Step Locations Except as provided by paragraph (v)(1) of this AD; at the applicable time specified in Table 4 of paragraph 1.E, ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010: Do an NDI (medium frequency eddy current, magneto optical imaging, C-scan, or ultrasonic phased array) for vertical chemmill cracking at locations specified in, and in accordance with paragraph 3.B.1.c. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Repeat the applicable inspections thereafter at intervals VerDate Mar<15>2010 14:58 Jan 18, 2012 Jkt 226001 not to exceed those specified in paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. (q) Fuselage Skin Inspections at Chem-mill Steps in General Pocket-to-Pocket Areas Except as provided by paragraph (v)(1) of this AD; at the applicable time specified in Tables 5 and 6 of paragraph 1.E, ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010: Do an NDI (medium frequency eddy current, magneto optical imaging, C-scan, or ultrasonic phased array) for horizontal chem-mill cracking in general pocket-to-pocket areas at specified locations in and in accordance with paragraph 3.B.1.d., 3.B.1.e., and 3.B.1.f., as applicable, of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Repeat the applicable inspections thereafter at intervals not to exceed those specified in Tables 5 and 6 of paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. (r) Inspection Exception For inspections required by paragraph (m) of this AD: It is not necessary to inspect the chem-mill steps under an existing repair installed using Boeing Special Attention Service Bulletin 737–53–1234, dated June 13, 2002; or Revision 1, dated March 31, 2005. (s) Repair of Cracking Found During Inspections Required by Paragraphs (o) Through (q) of This AD If any crack is found during any inspections required by paragraph (o), (p), or (q) of this AD, before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (x) of this AD. (t) Actions for Airplanes on Which Repairs Have Been Done Using Previous Service Information (1) For airplanes on which permanent repairs have been done in accordance with Boeing Special Attention Service Bulletin 737–53–1234, dated June 13, 2002, or Revision 1, dated March 31, 2005; except airplanes on which internal tear strap doublers were previously installed using a repair plan approved using the procedures specified in paragraph (x) of this AD: Within 6,000 flight cycles after the effective date of this AD, install internal tear strap doublers, in accordance with paragraph 3.B.3. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, except as provided by paragraph (v)(2) of this AD. Installation of internal tear strap doublers specified in this paragraph terminates the inspections required by paragraph (m) of this AD for the repaired area only. (2) For airplanes on which time-limited repairs have been installed in accordance with Boeing Special Attention Service Bulletin 737–53–1234, dated June 13, 2002, or Revision 1, dated March 31, 2005; except airplanes on which the permanent repair has been installed before the effective date of this AD in accordance with Boeing Special PO 00000 Frm 00016 Fmt 4702 Sfmt 4702 2673 Attention Service Bulletin 737–53–1234, dated June 13, 2002, or Revision 1, dated March 31, 2005: Within 3,000 flight cycles after the time limited repair is installed, or within 500 flight cycles after the effective date of the AD, whichever occurs later, do a detailed inspection for loose fasteners, in accordance with paragraph 3.B.4. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles until the permanent repair is installed in accordance with paragraph (n)(1) of this AD. If any loose fasteners are found, before further flight, replace the fasteners with new fasteners of the same type and size as specified in Figures 6, 35, and 36, as applicable, of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010. (3) For airplanes on which time-limited repairs have been installed in accordance with Boeing Special Attention Service Bulletin 737–53–1234, dated June 13, 2002, or Revision 1, dated March 31, 2005; except airplanes on which the permanent repair has been installed before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 737–53–1234, dated June 13, 2002, or Revision 1, dated March 31, 2005; before the effective date of this AD: Within 6,000 flight cycles after the time-limited repair is installed, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, make the repair permanent by replacing the blind fasteners in the time-limited repair with solid rivets, and install internal tear strap doublers, in accordance with paragraph 3.B.4. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, except as provided by paragraph (v)(2) of this AD. (u) Action Not in Accomplishment Instructions If any crack is found after the time-limited or permanent repair is installed, and Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, 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 (x) of this AD. (v) Exceptions to Boeing Alert Service Bulletin 737–53A1234, Revision 2, Dated November 24, 2010 (1) Where paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, specifies a compliance time relative to the ‘‘release of Revision 2 of this service bulletin,’’ this AD requires compliance within the specified compliance time after the effective date of this AD. (2) Where Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, 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 (x) of this AD. E:\FR\FM\19JAP1.SGM 19JAP1 2674 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules (3) Although Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, specifies reporting certain information to Boeing, this AD does not require that action. (w) Post-Repair Inspections The post-repair inspection specified in Table 7 of paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, is not required by this AD. Note 2: The damage tolerance inspections specified in Table 7 of paragraph 1.E., Compliance, of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, may be used in support of compliance with section 121.1109(c)(2) or 129.109(c)(2) of the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(c)(2)). The corresponding actions specified in the Accomplishment Instructions and Figures 40 and 41 of Boeing Alert Service Bulletin 737–53A1234, Revision 2, dated November 24, 2010, are not required in this AD. EMCDONALD on DSK29S0YB1PROD with PROPOSALS (x) Alternative Methods of Compliance (AMOCs) (1) The Manager, Seattle 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-ANMSeattle-ACO-AMOC-Requests@faa.gov. (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. (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. (4) AMOCs approved for AD 2005–13–27, Amendment 39–14164 (70 FR 36821, June 27, 2005), are approved as AMOCs for the corresponding requirements in this AD. https://www.myboeingfleet.com. You may review copies of the referenced 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. Issued in Renton, Washington, on January 6, 2012. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2012–859 Filed 1–18–12; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2012–0046; Directorate Identifier 2011–CE–040–AD] RIN 2120–AA64 Airworthiness Directives; Glasflugel Gliders Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Notice of proposed rulemaking (NPRM). AGENCY: We propose to adopt a new airworthiness directive (AD) for Glasflugel Models Standard Libelle201B, Club Libelle 205, Mosquito, and Kestrel gliders. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as corrosion damage to the elevator control rod that could lead to failure of the elevator control rod, possibly resulting in loss of control of the glider. We are issuing this proposed AD to require actions to address the unsafe condition on these products. DATES: We must receive comments on this proposed AD by March 5, 2012. ADDRESSES: You may send comments by (y) Related Information any of the following methods: (1) For more information about this AD, • Federal eRulemaking Portal: Go to contact Wayne Lockett, Aerospace Engineer, https://www.regulations.gov. Follow the Airframe Branch, ANM–120S, FAA, Seattle Aircraft Certification Office, 1601 Lind instructions for submitting comments. Avenue SW., Renton, Washington 98057– • Fax: (202) 493–2251. 3356; telephone (425) 917–6447; fax (425) • Mail: U.S. Department of 917–6590; email: wayne.lockett@faa.gov. Transportation, Docket Operations, (2) For service information identified in M–30, West Building Ground Floor, this AD, contact Boeing Commercial Room W12–140, 1200 New Jersey Airplanes, Attention: Data & Services Avenue SE., Washington, DC 20590. Management, P.O. Box 3707, MC 2H–65, • Hand Delivery: U.S. Department of Seattle, Washington 98124–2207; telephone Transportation, Docket Operations, (206) 544–5000, extension 1; fax (206) 766– 5680; email me.boecom@boeing.com; Internet M–30, West Building Ground Floor, VerDate Mar<15>2010 17:01 Jan 18, 2012 Jkt 226001 SUMMARY: PO 00000 Frm 00017 Fmt 4702 Sfmt 4702 Room W12–140, 1200 New Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. For service information identified in this proposed AD, contact Glasfaser ¨ Flugzeug-Service Hansjorg Streifeneder GmbH, D–72582 Grabenstetten, Germany; phone: +49(0)73821032, fax: +49(0)73821629; email: info@streifly.de; Internet: www.streifly.de/. You may review copies of the referenced service information at the FAA, Small Airplane Directorate, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329–4148. Examining the AD Docket You may examine the AD docket on the Internet at https:// www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone (800) 647–5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt. FOR FURTHER INFORMATION CONTACT: Jim Rutherford, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329–4165; fax: (816) 329–4090; email: jim.rutherford@faa.gov. SUPPLEMENTARY INFORMATION: Comments Invited We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include ‘‘Docket No. FAA–2012–0046; Directorate Identifier 2011–CE–040–AD’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments. We will post all comments we receive, without change, to https:// regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD. Discussion The European Aviation Safety Agency (EASA), which is the Technical Agent E:\FR\FM\19JAP1.SGM 19JAP1

Agencies

[Federal Register Volume 77, Number 12 (Thursday, January 19, 2012)]
[Proposed Rules]
[Pages 2669-2674]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-859]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1419; Directorate Identifier 2010-NM-281-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to supersede an existing airworthiness directive
(AD) that applies to certain The Boeing Company Model 737-300, -400,
and -500 series airplanes. The existing AD currently requires
repetitive inspections for cracking of the crown area of the fuselage
skin, and corrective actions if necessary. Since we issued that AD, we
received additional reports of cracking at the horizontal chem-mill
steps away from the lap joints over the entire crown area, and vertical
chem-mill cracks adjacent to the butt joints. This proposed AD would
add repetitive inspections for cracking using different inspection
methods and would inspect additional areas, and corrective actions if
necessary. This proposed AD would also require additional repairs to
previously repaired areas and repetitive inspections for loose
fasteners and replacement if necessary in certain previously repaired
areas. This proposed AD would also reduce certain compliance times and
extend certain other compliance times. We are proposing this AD to
detect and correct fatigue cracking of the fuselage skin, which could
cause the fuselage skin to fracture and fail, and result in rapid
decompression of the airplane.

DATES: We must receive comments on this proposed AD by March 5, 2012.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
Fax: (202) 493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
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; email me.boecom@boeing.com;
Internet https://www.myboeingfleet.com. You may review copies of the
referenced 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.

Examining the AD Docket

You may examine the AD docket on the Internet at https://www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (phone: (800) 647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.

FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-
6447; fax: (425) 917-6590; email: wayne.lockett@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2011-1419;
Directorate Identifier 2010-NM-281-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
We will post all comments we receive, without change, to https://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

On June 15, 2005, we issued AD 2005-13-27, amendment 39-14164 (70
FR 36821, June 27, 2005), for certain Boeing Model 737-300, -400, and -
500 series airplanes. That AD requires repetitive inspections for
cracking of the crown area of the fuselage skin, and corrective actions
if necessary. That AD resulted from a Model 737 fuselage structure test
and fatigue analysis that indicate fuselage skin cracking could occur
between 21,000 and 42,000 total flight cycles. We issued that AD to
detect and correct fatigue cracking of the fuselage skin, which could
cause the fuselage skin to fracture and fail, and result in rapid
decompression of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2005-13-27, amendment 39-14164 (70 FR 36821,
June 27, 2005), additional reports of cracking at the horizontal chem-
mill steps away from the lap joints over the entire crown area, and
vertical chem-mill cracks adjacent to the butt joints, have been
received. Although there were no changes to the applicability in AD
2005-13-17, we have changed paragraph (c) of the proposed AD to refer
to Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010.

Relevant Service Information

We reviewed Boeing Alert Service Bulletin 737-53A1234, Revision 2,
dated November 24, 2010. Boeing Special Attention Service Bulletin 737-
53-1234, Revision 1, dated March 31, 2005, was referred to for
accomplishing the actions in AD 2005-13-27, amendment 39-14164 (70 FR
36821, June 27, 2005). Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010, describes procedures for
repetitive non-destructive inspections (NDI) (medium

[[Page 2670]]

frequency eddy current, magneto optical imaging, C-scan, or ultrasonic
phased array) for cracking of the fuselage skin, and corrective actions
if necessary. The NDI inspections for cracking of the skin include:
Inspecting for horizontal chem-mill cracking above the S-4
and S-10 lap joints
Inspecting for horizontal chem-mill cracking in the shear
wrinkle areas
Inspecting for vertical chem-mill cracking at specified
locations
Inspecting for horizontal chem-mill cracking in general
pocket-to-pocket areas at specified locations.
The corrective actions include installing a permanent repair
(including related investigative actions and applicable corrective
actions), installing a time-limited repair (including related
investigative actions and applicable corrective actions), and
contacting Boeing for repair instructions and doing the repair. For the
temporary repair, the related investigative actions include a detailed
inspection for cracks of the skin and a detailed inspection for
corrosion and disbonding of the lap joint; and the corrective action is
contacting Boeing for repair instructions and doing the repair. For the
permanent repair, the related investigative actions include an NDI
inspection for cracks of the skin and fastener holes and a detailed
inspection for corrosion and disbonding of the skin; and the corrective
action is contacting Boeing for repair instructions and doing the
repair.
Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010, also describes procedures, for airplanes on which
permanent repairs have already been done, for installing internal tear
strap doublers.
Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010, also describes procedures, for airplanes on which
time-limited repairs have already been installed, for doing repetitive
detailed inspections for loose fasteners until the permanent repair is
installed; and making the repair permanent (including related
investigative actions and applicable corrective actions) by replacing
the blind fasteners in the time-limited repair with solid rivets, and
installing internal tear strap doublers. The related investigative
actions include an NDI for cracks of the fastener holes and skin, a
general visual inspection to determine if fasteners are installed
common to the chem-milled steps, and a detailed inspection for
corrosion and disbonding of the skin; and the corrective action is
contacting Boeing for repair instructions and doing the repair.
The repetitive NDI inspection intervals vary depending on the
configuration and the inspection option. Option 1 of Boeing Alert
Service Bulletin 737-53A1234, Revision 2, dated November 24, 2010,
specifies doing one of the following NDI; medium frequency eddy current
inspection, magneto optical imaging inspection, or C-scan inspection).
Option 2 specifies doing one NDI--an external ultrasonic phased array
inspection. The repetitive interval ranges between 500 flight cycles
and 2,400 flight cycles. Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010, also specifies that if the
inspection procedure is switched from Option 2 to Option 1, then the
next Option 1 inspection must be done within the Option 2 interval; and
that if the inspection procedure is switched from Option 1 to Option 2,
then the next two Option 2 inspections must be done within the Option 1
interval.
The inspection thresholds range from 25,000 total flight cycles to
81,000 total flight cycles, depending on the airplane configuration and
inspection location. The grace periods range from 500 to 2,400 flight
cycles or 1,800 flight hours, depending on the airplane configuration
and inspection location. The repetitive inspection intervals range from
500 to 2,400 flight cycles, or 1,800 to 2,400 flight hours, depending
on the inspection type and airplane configuration. For airplanes on
which a time-limited repair is done, the compliance time to do the
permanent repair is 6,000 flight cycles after doing the time-limited
repair.
Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010, also includes an exception to inspecting the chem-
mill steps under an existing external repair doubler, provided the
conditions specified below apply:
The repair was installed after November 24, 2010
The repair was approved by the FAA or by a Boeing
Commercial Airplanes Organization Designation Authorization (ODA) who
was authorized by the FAA to make such findings
The repair extends a minimum of three rows of fasteners on
each side of the chem-mill step line in the circumferential direction,
Or
The repair was approved by the FAA or by a Boeing
Commercial Airplanes Organization Designation Authorization (ODA) who
was authorized by the FAA to make such findings
The repair extends a minimum of 2 rows of \3/16\ inch
diameter fasteners on each side of the chem-mill step in the
circumferential direction with 5-6D fastener spacing
The repair is similar to Figure 201, Repair 31 of Figure
201 of Subject 53-00-01, ``Fuselage Skin--General,'' of the Boeing 737-
300, 737-400, or 737-500 Structural Repair Manual, with regard to
fastener type, size layout and pitch; repair part thickness and
material; and repair installation.

FAA's Determination

We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD would retain all of the requirements of AD 2005-
13-27, Amendment 39-14164 (70 FR 36821, June 27, 2005). This proposed
AD would add repetitive inspections for cracking using different
inspection methods and would inspect additional areas, and corrective
actions if necessary. This proposed AD would also require, for
airplanes on which the existing permanent repair was done, installing
internal tear strap doublers. This proposed AD would also require, for
airplanes on which the existing temporary repair was done, doing
repetitive inspections for loose fasteners and replacement if
necessary, and installing a permanent repair. This proposed AD would
also change (reducing some and extending others) initial compliance
times and repetitive intervals. This proposed AD would also require
accomplishing the actions specified in the service information
described previously, except as discussed under ``Differences Between
the Proposed AD and the Service Information.''

Differences Between the Proposed AD and the Service Information

The Accomplishment Instructions in Boeing Alert Service Bulletin
737-53A1234, Revision 2, dated November 24, 2010, do not provide a
procedure for replacing loose fasteners; however, this proposed AD
requires replacing any loose fastener with a new fastener of the same
type and size as specified in Figures 6, 35 and 36, as applicable, of
the Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1234, Revision 2, dated November 24, 2010.
Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010, specifies to contact the manufacturer for
instructions on how to

[[Page 2671]]

repair certain conditions, but this proposed AD would require repairing
those conditions in one of the following ways:
In accordance with a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) whom we have
authorized to make those findings.

Costs of Compliance

We estimate that this proposed AD affects 109 airplanes of U.S.
registry.
We estimate the following costs to comply with this proposed AD:

Estimated Costs
----------------------------------------------------------------------------------------------------------------
Action Labor cost Cost per product Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
Inspection (retained actions from 94 work-hours x $85 $7,990 per inspection $870,910.
AD 2005-13-27, Amendment per hour = $7,990. cycle.
39[dash]14164 (70 FR 36821, June
27, 2005).
New NDI Inspections (medium Up to 390 work-hours Up to $33,150 per Up to $3,613,350.
frequency eddy current, magneto x $85 per hour = inspection cycle.
optical imaging, C-scan, or $33,150.
ultrasonic phased array).
Install internal tear strap Up to 30 Up to $2,550......... Up to $277,950.
doublers (for airplanes on which work[dash]hours x
permanent repair was already $85 per hour =
done). $2,550.
* Inspection for loose fasteners 1 work-hour x $85 per $85.................. $9,265.
(for airplanes on which hour = $85.
temporary repair was already
done).
* Install permanent repair (for Up to 48 Up to $4,080......... Up to $444,720.
airplanes on which temporary work[dash]hours x
repair was already done). $85 per hour =
$4,080.
* Inspection adjacent to lap 3 work-hours x $85 $255................. $27,795.
joint repair. per hour = $255.
----------------------------------------------------------------------------------------------------------------
* The cost for this action is for one typical repair only.

We estimate the following costs to do any necessary repairs that
would be required based on the results of the proposed inspection. We
have no way of determining the number of aircraft that might need these
repairs:

On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Action Labor cost Parts cost Cost per product
----------------------------------------------------------------------------------------------------------------
Repair \1\....................... 209 work-hours x $85 None................. $17,765.
per hour = $17,765.
----------------------------------------------------------------------------------------------------------------
\1\ Repair cost estimate is for one typical repair only.

Authority for This Rulemaking

Title 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.
We 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.

Regulatory Findings

We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national Government and the States, or on the distribution
of power and responsibilities among the various levels of government.
For the reasons discussed above, I certify that the proposed
regulation:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),
(3) Will not affect intrastate aviation in Alaska, and
(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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing airworthiness directive
(AD) 2005-13-27, Amendment 39-14164 (70 FR 36821, June 27, 2005), and
adding the following new AD:

The Boeing Company: Docket No. FAA-2011-1419; Directorate Identifier
2010-NM-281-AD.

[[Page 2672]]

(a) Comments Due Date

The FAA must receive comments on this AD action by March 5,
2012.

(b) Affected ADs

This AD supersedes AD 2005-13-27, Amendment 39-14164 (70 FR
36821, June 27, 2005).

This AD applies to The Boeing Company Model 737-300, -400, and -
500 series airplanes, certificated in any category; as identified in
Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010.

(d) Subject

Joint Aircraft System Component (JASC)/Air Transport Association
(ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by reports of cracking at the horizontal
chem-mill steps away from the lap joints over the entire crown area,
and vertical chem-mill cracks adjacent to the butt joints. We are
issuing this AD to detect and correct fatigue cracking of the
fuselage skin, which could cause the fuselage skin to fracture and
fail, and result in rapid decompression of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified,
unless already done.

(g) Restatement of Requirements of AD 2005-13-27, Amendment 39-14164
(70 FR 36821, June 27, 2005): Initial Inspections per Boeing Special
Attention Service Bulletin 737-53-1234, Revision 1, Dated March 31,
2005

At the later of the times specified in paragraphs (g)(1) and
(g)(2) of this AD, perform detailed and eddy current inspections for
cracking of the crown area of the fuselage skin in accordance with
Part 1, including the ``Note,'' of the Work Instructions of Boeing
Special Attention Service Bulletin 737-53-1234, Revision 1, dated
March 31, 2005, except as provided by paragraph (j) of this AD.
Doing the inspections required by paragraph (m) of this AD
terminates the inspections required by this paragraph for the
corresponding inspection areas.
(1) Before the accumulation of the applicable total flight
cycles specified in the ``Threshold'' column of Table 1 of Figure 1
of Boeing Special Attention Service Bulletin 737-53-1234, Revision
1, dated March 31, 2005.
(2) Within 4,500 flight cycles after August 1, 2005 (the
effective date of AD 2005-13-27, Amendment 39-14164 (70 FR 36821,
June 27, 2005).

(h) Repetitive Inspections per Boeing Special Attention Service
Bulletin 737-53-1234, Revision 1, Dated March 31, 2005

Repeat either the detailed or eddy current inspections specified
in paragraph (g) of this AD at the applicable intervals specified in
paragraph (h)(1) or (h)(2) of this AD until paragraph (i)(1) or
(i)(2) of this AD has been done, as applicable. Doing the inspection
required by paragraph (m) of this AD terminates the inspections
required by this paragraph for the corresponding inspection area.
(1) Repeat the detailed inspections thereafter at intervals not
to exceed 1,200 flight cycles.
(2) Repeat the eddy current inspections thereafter at intervals
not to exceed 3,000 flight cycles.

(i) Permanent or Time-Limited Repair for Cracking Found During
Inspections in Accordance With Boeing Special Attention Service
Bulletin 737-53-1234, Revision 1, Dated March 31, 2005

If any cracking is found during any inspection required by
paragraph (g) or (h) of this AD, do the actions specified in
paragraph (i)(1) or (i)(2) of this AD in accordance with Boeing
Special Attention Service Bulletin 737-53-1234, Revision 1, dated
March 31, 2005, except as provided by paragraphs (j) and (k) of this
AD.
(1) Before further flight, do a permanent repair (including
related investigative actions and applicable corrective actions) in
accordance with Part 2 of the Work Instructions of Boeing Special
Attention Service Bulletin 737-53-1234, Revision 1, dated March 31,
2005. Doing a permanent repair ends the repetitive inspections
required by paragraph (h) of this AD for the repaired area only.
(2) Do the actions specified in paragraphs (i)(2)(i) and
(i)(2)(ii) of this AD at the time specified in the applicable
paragraph. Doing a time-limited repair ends the repetitive
inspections required by paragraph (h) of this AD for the repaired
area only.
(i) Before further flight, do a time-limited repair (including
related investigative actions and applicable corrective actions) in
accordance with Part 3 of the Work Instructions of Boeing Special
Attention Service Bulletin 737-53-1234, Revision 1, dated March 31,
2005.
(ii) At the times specified in Figure 8 of Boeing Special
Attention Service Bulletin 737-53-1234, Revision 1, dated March 31,
2005, do the related investigative and corrective actions in
accordance with Part 3 of the Work Instructions of Boeing Special
Attention Service Bulletin 737-53-1234, Revision 1, dated March 31,
2005.

(j) Contact the FAA

Where Boeing Special Attention Service Bulletin 737-53-1234,
Revision 1, dated March 31, 2005, specifies to contact Boeing for
appropriate action: Before further flight, repair according to a
method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA; or according to data meeting the certification
basis of the airplane approved by an Authorized Representative for
the Boeing Delegation Option Authorization Organization who has been
authorized by the Manager, Seattle ACO, to make those findings; or
using a method approved in accordance with the procedures specified
in paragraph (x) of this AD. For a repair method to be approved, the
approval must specifically reference this AD.

(k) No Reporting for Actions in Boeing Special Attention Service
Bulletin 737-53-1234, Revision 1, Dated March 31, 2005

Although Boeing Special Attention Service Bulletin 737-53-1234,
Revision 1, dated March 31, 2005, specifies reporting certain
information to Boeing, this AD does not require that action.

(l) Actions Accomplished According to Previous Issue of Service
Bulletin

Actions done before August 1, 2005, in accordance with Boeing
Special Attention Service Bulletin 737-53-1234, dated June 13, 2002,
are acceptable for compliance with the corresponding actions
required by paragraphs (g), (h), and (i) of this AD.

(m) New Requirements of This AD: Fuselage Skin Inspections at Chem-Mill
Steps Common to Lap Joints

Except as provided by paragraph (v)(1) of this AD; at the
applicable time specified in Tables 1 and 2 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010: Do a non-destructive inspection
(NDI) (medium frequency eddy current, magneto optical imaging, C-
scan, or ultrasonic phased array) for horizontal chem-mill cracking
above the S-4 and S-10 lap joints, in accordance with paragraph
3.B.1.a. of the Accomplishment Instructions of Boeing Alert Service
Bulletin 737-53A1234, Revision 2, dated November 24, 2010, except as
provided by paragraph (r) of this AD. Repeat the applicable
inspections thereafter at intervals not to exceed those specified in
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin
737-53A1234, Revision 2, dated November 24, 2010. Accomplishment of
the inspections required by this paragraph terminates the
requirements of paragraphs (g) and (h) of this AD for the
corresponding inspection areas.

Note 1: Option 1 of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010, specifies doing one of the
following NDI; medium frequency eddy current inspection, magneto
optical imaging inspection, or C-scan inspection. Option 2 specifies
doing one NDI--an external ultrasonic phased array inspection. These
options have different compliance times after the initial
inspection.

(n) Permanent or Time-Limited Repair for Cracking Found During
Paragraph (m) Inspections

If any cracking is found during any inspection required by
paragraph (m) of this AD, do the actions specified in paragraph
(n)(1) or (n)(2) of this AD.
(1) Before further flight, do a permanent repair (including
related investigative actions and applicable corrective actions) in
accordance with Part 2 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1234, Revision 2, dated November 24,
2010, except as provided by paragraph (v)(2) of this AD. Doing a
permanent repair ends the repetitive inspections required by
paragraph (m) of this AD for the repaired area only.
(2) Do the actions specified in paragraphs (n)(2)(i),
(n)(2)(ii), and (n)(2)(iii) of this AD at

[[Page 2673]]

the time specified in the applicable paragraph. Doing a time-limited
repair ends the repetitive inspections required by paragraph (m) of
this AD for the repaired area only.
(i) Before further flight, do a time-limited repair (including
related investigative actions and applicable corrective actions) in
accordance with Part 4 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1234, Revision 2, dated November 24,
2010, except as provided by paragraph (v)(2) of this AD.
(ii) Within 3,000 flight cycles after the time-limited repair
was installed as specified in paragraph (n)(2)(i) of this AD or
within 500 flight cycles after the effective date of this AD,
whichever occurs later, do a detailed inspection for loose
fasteners, in accordance with Part 4 of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1234, Revision
2, dated November 24, 2010. Repeat the inspection thereafter at
intervals not to exceed 3,000 flight cycles until the permanent
repair required by paragraph (n)(2)(iii) of this AD is done. If any
loose fasteners are found, before further flight, replace the
fasteners with new fasteners of the same type and size as specified
in Figures 6, 35 and 36 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1234, Revision 2, dated November 24,
2010.
(iii) Within 6,000 flight cycles after the time-limited repair
was installed as specified in paragraph (n)(2)(i) of this AD, do the
permanent repair specified in paragraph (n)(1) of this AD.

(o) Fuselage Skin Inspections at Chem-mill Steps Common to Shear
Wrinkle Areas

Except as provided by paragraph (v)(1) of this AD; at the
applicable time specified in Table 3 of paragraph 1.E,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010: Do an NDI (medium frequency
eddy current, magneto optical imaging, C-scan, or ultrasonic phased
array) for horizontal chem-mill cracking in the shear wrinkle areas,
in accordance with paragraph 3.B.1.b of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1234, Revision
2, dated November 24, 2010. Repeat the applicable inspections
thereafter at intervals not to exceed those specified in paragraph
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010.

(p) Fuselage Skin Inspections at Specified Vertical Chem-mill Step
Locations

Except as provided by paragraph (v)(1) of this AD; at the
applicable time specified in Table 4 of paragraph 1.E,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010: Do an NDI (medium frequency
eddy current, magneto optical imaging, C-scan, or ultrasonic phased
array) for vertical chem-mill cracking at locations specified in,
and in accordance with paragraph 3.B.1.c. of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1234, Revision
2, dated November 24, 2010. Repeat the applicable inspections
thereafter at intervals not to exceed those specified in paragraph
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010.

(q) Fuselage Skin Inspections at Chem-mill Steps in General Pocket-to-
Pocket Areas

Except as provided by paragraph (v)(1) of this AD; at the
applicable time specified in Tables 5 and 6 of paragraph 1.E,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010: Do an NDI (medium frequency
eddy current, magneto optical imaging, C-scan, or ultrasonic phased
array) for horizontal chem-mill cracking in general pocket-to-pocket
areas at specified locations in and in accordance with paragraph
3.B.1.d., 3.B.1.e., and 3.B.1.f., as applicable, of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1234, Revision 2, dated November 24, 2010. Repeat the applicable
inspections thereafter at intervals not to exceed those specified in
Tables 5 and 6 of paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1234, Revision 2, dated November 24, 2010.

(r) Inspection Exception

For inspections required by paragraph (m) of this AD: It is not
necessary to inspect the chem-mill steps under an existing repair
installed using Boeing Special Attention Service Bulletin 737-53-
1234, dated June 13, 2002; or Revision 1, dated March 31, 2005.

(s) Repair of Cracking Found During Inspections Required by Paragraphs
(o) Through (q) of This AD

If any crack is found during any inspections required by
paragraph (o), (p), or (q) of this AD, before further flight, repair
the crack using a method approved in accordance with the procedures
specified in paragraph (x) of this AD.

(t) Actions for Airplanes on Which Repairs Have Been Done Using
Previous Service Information

(1) For airplanes on which permanent repairs have been done in
accordance with Boeing Special Attention Service Bulletin 737-53-
1234, dated June 13, 2002, or Revision 1, dated March 31, 2005;
except airplanes on which internal tear strap doublers were
previously installed using a repair plan approved using the
procedures specified in paragraph (x) of this AD: Within 6,000
flight cycles after the effective date of this AD, install internal
tear strap doublers, in accordance with paragraph 3.B.3. of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1234, Revision 2, dated November 24, 2010, except as provided by
paragraph (v)(2) of this AD. Installation of internal tear strap
doublers specified in this paragraph terminates the inspections
required by paragraph (m) of this AD for the repaired area only.
(2) For airplanes on which time-limited repairs have been
installed in accordance with Boeing Special Attention Service
Bulletin 737-53-1234, dated June 13, 2002, or Revision 1, dated
March 31, 2005; except airplanes on which the permanent repair has
been installed before the effective date of this AD in accordance
with Boeing Special Attention Service Bulletin 737-53-1234, dated
June 13, 2002, or Revision 1, dated March 31, 2005: Within 3,000
flight cycles after the time limited repair is installed, or within
500 flight cycles after the effective date of the AD, whichever
occurs later, do a detailed inspection for loose fasteners, in
accordance with paragraph 3.B.4. of the Accomplishment Instructions
of Boeing Alert Service Bulletin 737-53A1234, Revision 2, dated
November 24, 2010. Repeat the inspection thereafter at intervals not
to exceed 3,000 flight cycles until the permanent repair is
installed in accordance with paragraph (n)(1) of this AD. If any
loose fasteners are found, before further flight, replace the
fasteners with new fasteners of the same type and size as specified
in Figures 6, 35, and 36, as applicable, of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1234, Revision
2, dated November 24, 2010.
(3) For airplanes on which time-limited repairs have been
installed in accordance with Boeing Special Attention Service
Bulletin 737-53-1234, dated June 13, 2002, or Revision 1, dated
March 31, 2005; except airplanes on which the permanent repair has
been installed before the effective date of this AD in accordance
with Boeing Special Attention Service Bulletin 737-53-1234, dated
June 13, 2002, or Revision 1, dated March 31, 2005; before the
effective date of this AD: Within 6,000 flight cycles after the
time-limited repair is installed, or within 1,000 flight cycles
after the effective date of this AD, whichever occurs later, make
the repair permanent by replacing the blind fasteners in the time-
limited repair with solid rivets, and install internal tear strap
doublers, in accordance with paragraph 3.B.4. of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1234, Revision
2, dated November 24, 2010, except as provided by paragraph (v)(2)
of this AD.

(u) Action Not in Accomplishment Instructions

If any crack is found after the time-limited or permanent repair
is installed, and Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010, 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 (x) of this AD.

(v) Exceptions to Boeing Alert Service Bulletin 737-53A1234, Revision
2, Dated November 24, 2010

(1) Where paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1234, Revision 2, dated November 24, 2010,
specifies a compliance time relative to the ``release of Revision 2
of this service bulletin,'' this AD requires compliance within the
specified compliance time after the effective date of this AD.
(2) Where Boeing Alert Service Bulletin 737-53A1234, Revision 2,
dated November 24, 2010, 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
(x) of this AD.

[[Page 2674]]

(3) Although Boeing Alert Service Bulletin 737-53A1234, Revision
2, dated November 24, 2010, specifies reporting certain information
to Boeing, this AD does not require that action.

(w) Post-Repair Inspections

The post-repair inspection specified in Table 7 of paragraph
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1234,
Revision 2, dated November 24, 2010, is not required by this AD.

Note 2: The damage tolerance inspections specified in Table 7
of paragraph 1.E., Compliance, of Boeing Alert Service Bulletin 737-
53A1234, Revision 2, dated November 24, 2010, may be used in support
of compliance with section 121.1109(c)(2) or 129.109(c)(2) of the
Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR
129.109(c)(2)). The corresponding actions specified in the
Accomplishment Instructions and Figures 40 and 41 of Boeing Alert
Service Bulletin 737-53A1234, Revision 2, dated November 24, 2010,
are not required in this AD.

(x) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Seattle 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.
(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.
(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.
(4) AMOCs approved for AD 2005-13-27, Amendment 39-14164 (70 FR
36821, June 27, 2005), are approved as AMOCs for the corresponding
requirements in this AD.

(y) Related Information

(1) For more information about this AD, contact Wayne Lockett,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue SW., Renton, Washington
98057-3356; telephone (425) 917-6447; fax (425) 917-6590; email:
wayne.lockett@faa.gov.
(2) 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; email
me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You
may review copies of the referenced 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.

Issued in Renton, Washington, on January 6, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2012-859 Filed 1-18-12; 8:45 am]
BILLING CODE 4910-13-P

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