AD 2010-20-08

The FAA is superseding an existing airworthiness directive (AD), which applies to all Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747- 400F, and 747SR series airplanes. That AD currently requires repetitive inspections to find cracking of the web, strap, inner chords, and inner chord angle of the forward edge frame of the number 5 main entry door cutouts, and repair, if necessary. This new AD requires expanding the inspection areas to include the frame segment between stringers 16 and 23. This AD reinstates the repetitive inspections specified above for certain airplanes. This AD also requires repetitive inspections for cracking of repairs. This AD results from additional reports of cracks that have been found in the strap and inner chord of the forward edge frame of the number 5 main entry door cutouts, between stringers 16 and 23. We are issuing this AD to detect and correct such cracks. This condition, if not corrected, could cause damage to the adjacent body structure, which could result in depressurization of the airplane in flight.

Final rule.

2010-20-08 The Boeing Company: Amendment 39-16442. Docket No. FAA- 2009-1069; Directorate Identifier 2009-NM-036-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective November 9, 2010. \n\nAffected ADs \n\n\t(b) This AD supersedes AD 2001-16-02, Amendment 39-12370. \n\nApplicability \n\n\t(c) This AD applies to The Boeing Company Model 747-100, 747- 100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR series airplanes, certificated in any category, having line numbers 1 through 1419 inclusive; except for Model 747-400 series airplanes that have been modified into the 747-400 large cargo freighter configuration. \n\nSubject \n\n\t(d) Air Transport Association (ATA) of America Code 53: Fuselage. \n\nUnsafe Condition \n\n\t(e) This AD results from additional reports of cracks that have been found in the strap and inner chord of the forward edge frame of the number 5 main entry door cutouts, between stringers 16 and 23. Based on these reports, we have determined that the frame segment between stringers 16 and 23 is also susceptible to the unsafe condition. The Federal Aviation Administration is issuing this AD to detect and correct such cracks. This condition, if not corrected, could cause damage to the adjacent body structure, which could result in depressurization of the airplane in flight. \n\nCompliance \n\n\t(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\nRestatement of Requirements of AD 2001-16-02, With New Service Information \n\nRepetitive Inspections for Frame Segment Between Stringers 23 and 31 (No Terminating Action) \n\n\t(g) For airplanes having line numbers 1 through 1304 inclusive: Inspect the airplane for cracks between stringers 23 and 31 per Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001; or Boeing Alert Service Bulletin 747-53A2450, Revision 5,dated January 29, 2009; at the later of the times specified in either paragraph (h) or (i) of this AD, per Table 1, as follows. After the effective date of this AD, use only Revision 5 of Boeing Alert Service Bulletin 747-53A2450, to accomplish the required inspection. \n\n\tTable 1-- Inspection Requirements\n\n\nType of Inspection\nArea to inspect\n(1)\tDetailed Visual\nStrap inner chords forward and aft of the web, and exposed web adjacent to the inner chords on station 2231 frame from stringer 23 through 31 per Figure 5 or Figure 6 of the service bulletin, as applicable\n(2)\tSurface High Frequency Eddy Current (HFEC)\nStation 2231 inner chord angles at lower main sill interface per Figure 5 or Figure 6 of the service bulletin, as applicable\n(3)\tOpen Hole HFEC\nStation 2231 frame fastener locations per Figures 4 and 7, and either Figure 5 or 6 of the service bulletin, as applicable\n(4)\tSurface HFEC\nAround fastener locations on station 2231 inner chords from stringer 23 through 31 per Figure 5 or Figure 6 of the service bulletin, as applicable\n(5)\tLow Frequency Eddy Current\nStation 2231 frame strap in areas covered by the reveal per Figure 5 or Figure 6 of the service bulletin, as applicable\n\n\n\t(h) Do the inspections specified in paragraph (g) of this AD at the applicable times specified in paragraph (h)(1) or (h)(2) of this AD. Repeat the inspections at intervals not to exceed 3,000 flight cycles. \n\n\t(1) Do the inspections per Table 1 of this AD at the applicable time specified in the logic diagram in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001. Where the compliance time in the logic diagram specifies a compliance time beginning, "from receipt of this service bulletin,'' this AD requires that the compliance time begin "after September 12, 2001 (the effective date of AD 2001-16- 02).'' \n\n\t(2) After the effective date of this AD, do the inspections per Table 1 of this AD at the applicablecompliance time specified in paragraph 1.E., "Compliance'' of the Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. Where the compliance time in Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001, specifies a compliance time beginning, "after the date on Revision 2 of this service bulletin,'' this AD requires that the compliance time begin "after September 12, 2001 (the effective date of AD 2001-16-02).'' \n\n\t(i) Within 3,000 flight cycles after accomplishment of the inspections specified in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, dated May 4, 2000; or Revision 1, dated July 6, 2000; repeat the inspections specified in paragraph (g) of this AD at intervals not to exceed 3,000 flight cycles. \n\n\tNote 1: There is no terminating action currently available for the inspections required by paragraph (g) of this AD. \n\n\tNote 2: Where there are differences between the AD and Boeing Alert Service Bulletin 747-53A2450, the AD prevails. \n\nNew Requirements of This AD \n\nAdditional Repetitive Inspections (For Frame Segment Between Stringers 16 and 23) \n\n\t(j) For all airplanes: Before the accumulation of 16,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do a detailed inspection, an open hole high frequency eddy current (HFEC) inspection, a surface HFEC inspection, and a subsurface low frequency eddy current (LFEC) inspection for cracking of the forward edge frame of the number 5 main entry door cutouts, at station 2231, between stringers 16 and 23; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. Repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles. \n\n\tNote 3: The part number of the nut for fastener code "K'' in Figure 7 of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009,should be "BACN10JC3CD,'' instead of "BACB30JC3CD.'' In addition, the part number of the optional nut for this fastener code should be "BACN10YR3CD,'' instead of "BACN10YR4CD.'' \n\nRepetitive Inspections for Line Numbers 1305 and On (For Frame Segment Between Stringers 23 and 31) \n\n\t(k) For airplanes having line numbers 1305 and on: Before 16,000 total flight cycles or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do a detailed inspection, an open hole HFEC inspection, a surface HFEC inspections, and a subsurface LFEC inspection for cracking of the forward edge frame of the number 5 main entry door cutouts, at station 2231, between stringers 23 and 31; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 53A2450, Revision 5, dated January 29, 2009. Repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles. \n\nCorrective Action \n\n\t(l) If any crack is found during any inspection required by this AD, before further flight, repair the crack in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings; or in accordance with Boeing Alert Service Bulletin 747- 53A2450, Revision 5, dated January 29, 2009. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD. As of the effective date of this AD, repair the crack using a method approved in accordance with the procedures specified in paragraph (o) of this AD. \n\nPost-Repair Inspections \n\n\t(m) Except as required by paragraph (n) of this AD, for airplanes on which the forward edge frame of the number 5 main entry door cutouts, at station 2231, between stringers 16 and 31, is repaired in accordance with Boeing Alert Service Bulletin 747- 53A2450: Within 3,000 flight cycles after doing the repair or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do the detailed, LFEC, and HFEC inspections of the repaired area for cracks in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. If no cracking is found, repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles. If any crack is found, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (o) of this AD. Doing the inspections specified in paragraph (m) of this AD terminates the repetitive inspections required by paragraphs (g), (h), (i), (j), and (k) of this AD for the repaired area. \n\n\t(n) For any frame that is repaired in accordance with a method other than the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, do the inspection in accordance with a method approved in accordance with the procedures specified in paragraph (o) of this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(o)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to Attn: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437; fax (425) 917-6590; Or, e-mail information to 9-ANM-Seattle-ACO-AMOC- Requests@faa.gov. \n\n\t(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD. \n\n\t(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\n\t(4) AMOCs approved previously in accordance with AD 2001-16-02, amendment 39-12370, are approved as AMOCs for the corresponding provisions of paragraphs (g), (h), (i), and (l) of this AD. \n\nMaterial Incorporated by Reference \n\n\t(p) You must use Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, to do the actions required by this AD, unless the AD specifies otherwise. \n\n\t(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. \n\n\t(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; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\n\t(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221. \n\n\t(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http:// www.archives.gov/federal_register/code_of_federal_regulations/ ibr_locations.html.

Discussion \n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD to supersede AD 2001-16-02, amendment 39- 12370 (66 FR 41440, August 8, 2001). The existing AD applies to certain Model 747 series airplanes. That NPRM was published in the Federal Register on November 20, 2009 (74 FR 60215). That NPRM proposed to continue to require repetitive inspections to find cracking of the web, strap, inner chords, and inner chord angle of the forward edge frame of the number 5 main entry door cutouts between stringers 23 and 31, and repair, if necessary. The NPRM also proposed to require expanding the inspection areas to include the frame segment between stringers 16 and 23; reinstating the repetitive inspections specified for certain airplanes; and adding repetitive inspections for cracking of repairs. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been received on the NPRM. \n\nRequest To Exclude Large Cargo Freighters (LCFs) From the AD Applicability \n\n\tBoeing requests we change the applicability in paragraph (c) of the NPRM to exclude LCFs. Boeing states that during modification into the LCF configuration, the 46-section from station 1960 to station 2360 was removed from the airplane. Boeing also states that this segment of the airplane was replaced with a new swing-zone and 47-section. \n\n\tWe agree with Boeing's request for the reason provided by the commenter. We have revised paragraph (c) of this AD accordingly. \n\nRequest for Clarification of the AD Applicability \n\n\tAn anonymous commenter requests that we clarify the applicability of the NPRM. The commenter notes that, in accordance with paragraph (c) of the NPRM, the proposed AD would be applicable to Boeing Model 747- 400F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2450, Revision 5,dated January 29, 2009. The commenter states that after reviewing this sentence in light of Revision 5 of the service bulletin, it was discovered that line number 1399 (i.e. variable number RL534) is not affected by Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, and therefore is not affected by the proposed AD. \n\n\tThe commenter also notes that paragraph (j) of the NPRM states, "For all airplanes: Before the accumulation of 16,000 total flight cycles * * *'' The commenter states that this sentence is confusing for airplane line number 1399 (i.e. variable number RL534), since this airplane is not affected by Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. The commenter states that this airplane is structurally the same as the other affected airplanes, and therefore it should be affected by the NPRM. \n\n\tWe disagree with the commenter's remark that line number 1399 is not affected by this AD. The "Effectivity'' paragraph in the Summary section of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, specifies "all 747 airplanes.'' Also, the Note in paragraph 1.A., "Effectivity,'' of Boeing Alert Service Bulletin 747- 53A2450, Revision 5, dated January 29, 2009, specifies that "airplanes after line number 1397 are also affected by this service bulletin.'' We acknowledge there may be confusion because the Note in paragraph 1.A., "Effectivity,'' of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, also states that "the effectivity list shown below is complete for airplanes through line number 1397.'' \n\n\tWe find that clarification of paragraph (c) of this AD is necessary. All Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747- 200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR series airplanes (line numbers 1 through 1419 inclusive) are affected by this AD except for the airplanes mentioned in the previous comment, "Request to Exclude Large Cargo Freighters (LCF) from the Applicability.'' Line numbers 1420 and subsequent are not affected by the identified unsafe condition because those line numbers correspond to Model 747-8 and 747-8F series airplanes, which are still being certified and have a different configuration than the airplanes identified in this AD. \n\nRequest To Update Delegation of Authority \n\n\tBoeing requests that we change Delegation Option Authorization (DOA) holder to Boeing Commercial Airplanes Organization Designation Authorization (ODA). \n\tWe agree with Boeing's request to update the delegation of authority. Boeing Commercial Airplanes has received an Organization Designation Authorization (ODA), which replaces the previous designation as a Delegation Option Authorization (DOA) holder. We have revised paragraph (o)(3) of this AD to add delegation of authority to Boeing Commercial Airplanes ODA to approve an alternative method of compliance (AMOC) for any repair required by this AD. \n\n\tWe alsohave revised paragraph (l) of this AD to delegate the authority to approve an alternative method of compliance for any repair required by this AD to the Boeing Commercial Airplanes ODA rather than a Designated Engineering Representative. \n\nRequest To Do Inspections in Accordance With the Structural Repair Manual (SRM) \n\n\tBoeing requests that for any frame repaired in accordance with the SRM, the inspections also can be done in accordance with the SRM. Boeing requests that the following sentence be added to paragraph (n) of this AD: "For any frame that is repaired in accordance with the 747-400 SRM 53-60-15, Figure 201, Repair 5, do the inspection, including the threshold and intervals in accordance with the SRM.'' \n\n\tBoeing states that the SRM was designed to add reinforcing steel straps, which will reduce the stress level in the edge frame and therefore allow an increased threshold of 20,000 flight cycles after the repair. \n\n\tWe do not agree with Boeing's request to do the inspections in accordance with the SRM. We have not been provided with any data to substantiate such a request, and further evaluation is needed. However, under the provisions of paragraph (o)(1) of this AD, we may consider requests for approval of an AMOC if sufficient data are submitted to substantiate that an alternative inspection plan would provide an acceptable level of safety. We have not changed the AD regarding this issue. \n\nRequest To Clarify Paragraph (i) of the NPRM \n\n\tNorthwest Airlines (NWA) requests that we clarify paragraph (i) of the NPRM. NWA states that it finds paragraph (i) of the NPRM to be "awkward.'' NWA states that paragraph (g) of the NPRM specifies to use only Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, after the effective date of the AD. NWA states that paragraph (i) of the proposed NPRM directs the reader to Figure 1 of Boeing Alert Service Bulletin 747-53A2450, dated May 4, 2000; or Revision 1, dated July 6, 2000; and that Figure 1 has been deleted from Revision 5. NWA recommends that paragraph (i) of the NPRM be revised to specify: "Within 3,000 flight cycles after accomplishment of the inspections previously specified in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, dated May 4, 2000, or Revision 1, dated July 6, 2000, repeat inspections at intervals not to exceed 3,000 flight cycles as specified in Table 1 of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009.'' \n\n\tWe disagree with NWA's request to change paragraph (i) of this AD. For clarification, paragraph (g) of this final rule restates the inspection requirements of AD 2001-16-02, and paragraph (i) of this final rule provides the repetitive interval for those inspections. The compliance times and the repetitive inspection intervals for the inspections have not changed; therefore, using Figure 1 of the service bulletin as the reference for the compliance time is correct. We have not changed the AD in this regard. \n\nRequest To Correct Typographical Errors \n\n\tAll Nippon Airways (ANA) requests that certain part numbers be corrected in the NPRM. ANA notes that paragraphs (h), (i), (j), and (k) of the NPRM would require initial and repetitive inspections of the STA 2231 frame, in accordance with Boeing Alert Service Bulletin 747- 53A2450, Revision 5, dated January 29, 2009. ANA states that it found several typographical errors on the code "K'' in Figure 7 of this service bulletin. ANA asserts that the part number of the nut should be "BACN10JC3CD,'' instead of "BACB30JC3CD.'' ANA also states that the part number should be "BACN10YR3CD,'' instead of "BACN10YR4CD.'' ANA states that Boeing concurs with this error and that Boeing will issue a new information notice with the correct information. \n\n\tWe agree with ANA's request that the part numbers referenced by the commenter should be corrected. Since the issuance of the NPRM, Boeing has issued Service Bulletin Information Notice 747-53A2450IN 04, dated May 3, 2010, specifying the correct part numbers. We have added a new Note 3 to this AD to reference the correct part numbers. \n\nRequest To Correct Editorial Error \n\n\tBoeing requests that an editorial error be corrected in paragraph (l) of the NPRM. Boeing states that the first sentence in paragraph (l) of the NPRM reads: "* * * required this AD. * * *'' Boeing states that the word "by'' should be inserted into the sentence to read: "* * * required by this AD. * * *'' \n\n\tWe agree with Boeing and have corrected the editorial error. We have revised paragraph (l) of this AD in this regard. \n\nExplanation of Change Made to This AD \n\n\tWe have revised this AD to identify the legal name of the manufacturer as published in the most recent type certificate data sheet for the affected airplane models. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comments that have been received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nExplanation of Changes to Costs of Compliance \n\n\tSince issuance of the NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate. \n\nCosts of Compliance \n\n\tThere are about 163 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\t\t\t\t\t\tEstimated Costs\n\n\nAction\nWork hours\nAverage labor rate per hour\nParts\nCost per airplane\nNumber of U.S.-registered airplanes\nFleet cost\nInspections (required by AD 2001-16-02)\n16\n$85\nNone\n$1,360 per inspection cycle\n163\n$221,680 per inspection cycle \nInspections (new action)\n28 depending on airplane configuration\n$85\nNone\nUp to $2,380 per inspection cycle, depending on airplane configuration\n163\nUp to $387,940 per inspection cycle, depending on airplane configuration\n\nAuthority for This Rulemaking \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\n\tWe are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, "General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\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\n\tFor the reasons discussed above, I certify that this AD: \n\n\t(1) Is not a "significant regulatory action'' under Executive Order 12866; \n\n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\n\t(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by removing amendment 39-12370 (66 FR 41440, August 8, 2001) and by adding the following new airworthiness directive (AD):