Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): \n\n2016-25-05 The Boeing Company: Amendment 39-18731; Docket No. FAA- 2015-5816; Directorate Identifier 2015-NM-029-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective January 25, 2017. \n\n(b) Affected ADs \n\n\n\tThis AD affects AD 2006-10-16, Amendment 39-14600 (71 FR 28570, May 17, 2006) (''AD 2006-10-16''). \n\n(c) Applicability \n\n\n\tThis AD applies to all 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, 747SR, and 747SP series airplanes; certificated in any category. \n\n(d) Subject \n\n\n\tAir Transport Association (ATA) of America Code 55, Stabilizers. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of cracking found in the splice plates, hinge fittings, terminal fittings, the upper skin of the outboard and center sections, upper chord, and rear spar webs before reaching the inspection interval specified in AD 2006-10-16. Cracked and fractured Maraging steel fasteners were also found. We are issuing this AD to detect and correct this cracking, which could lead to reduced structural capability of the outboard and center sections of the horizontal stabilizer and could result in loss of control of the airplane. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Repetitive Inspections/Investigative and Corrective Actions \n\n\n\tAt the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, except asrequired by paragraphs (h)(1) and (h)(2) of this AD: Do the applicable actions specified in paragraphs (g)(1), (g)(2), (g)(3), and (g)(4) of this AD, and all applicable related investigative and corrective actions, in accordance with the applicable part of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, except as required by paragraph (h)(3) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspections specified in paragraphs (g)(1), (g)(2), (g)(3), and (g)(4) of this AD at the applicable times specified in paragraph 1.E., ''Compliance,'' of Boeing Service Bulletin 747- 55A2050, Revision 2, dated January 23, 2015. \n\t(1) For Group 1 through 3 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Do non- destructive test (NDT) inspections (ultrasonic, high frequency eddy current, and low frequency eddy current inspections) or open-hole NDT inspections (high frequency eddy current inspections) of Zone B for cracking, in accordance with Part 3 or Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, as applicable. Accomplishing a Zone B inspection required by this paragraph terminates the inspections required by paragraph (g) of AD 2006-10-16 for the inspected area only. \n\t(2) For Group 4 through 6 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Do open- hole NDT inspections (high frequency eddy current inspections) of Zone B for cracking, in accordance with Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. Accomplishing a Zone B inspection required by this paragraph terminates the inspections required by paragraph (i) of AD 2006-10-16 for the inspected area only. \n\t(3) For Group 7 through 9 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Do inspections of Zone A (detailed or high frequency eddy current inspections) and Zone B (open-hole high frequency eddy current inspections) for cracking, in accordance with Part 1, Part 2, or Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, as applicable. Accomplishing Zone A and Zone B inspections required by this paragraph terminates the inspections required by paragraphs (f), (i), and (l) of AD 2006-10-16 for the inspected area only. \n\t(4) For Group 1 through 3 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Do an inspection of Zone C Maraging or H-11 steel fasteners to determine whether fasteners are magnetic, in accordance with Part 6 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\n(h) Exceptions to Service Bulletin Specifications \n\n\n\t(1) Where Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, specifies a compliance time ''after the Revision 2 date of this service bulletin,'' this AD requires compliance within the specified compliance time after the effective date of this AD. \n\t(2) The Condition column of Table 1 of paragraph 1.E., ''Compliance,'' of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, refers to airplanes with certain total flight cycles and total flight hours. This AD, however, applies to the \n\n((Page 93589)) \n\nairplanes with the specified total flight cycles and total flight hours as of the effective date of this AD. \n\t(3) Where Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD. \n\n(i) Optional Terminating Action \n\n\n\t(1) For Group 1 through 3 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Accomplishing the Zone B modification, including all applicable related investigative and corrective actions, specified in Part 7 of the Accomplishment Instructions of Boeing Service Bulletin 747- 55A2050, Revision 2, dated January 23, 2015, except as required by paragraph (h)(3) of this AD, terminates the repetitive inspections specified in paragraphs (i)(1)(i) through (i)(1)(iv) of this AD for the modified area only. \n\t(i) Inspections required by paragraph (g)(1) of this AD for Zone B, as specified in Part 3 and Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(ii) Inspections required by paragraph (g)(4) of this AD for Zone C, as specified in Part 6 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(iii) Inspections required by paragraph (g) of AD2006-10-16 for Zone B, as specified in Part 3 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(iv) Inspections required by paragraph (k) of AD 2006-10-16 for Zone C, as specified in Part 5 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(2) For Group 1 through 3 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Accomplishing the Zone B open-hole NDT inspection, repairing any cracking as applicable, and replacing fasteners as specified in Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 747- 55A2050, Revision 2, dated January 23, 2015, terminates the actions specified in paragraphs (i)(2)(i) and (i)(2)(ii) of this AD for the inspected area only. \n\t(i) The inspections required by paragraph (g)(4) of this AD for Zone C, as specified in Part 6 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(ii) The repetitive inspections required by paragraph (k) of AD 2006-10-16 for Zone C, as specified in Part 5 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(3) For Group 4 through 9 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Accomplishing the Zone B modification, including all applicable related investigative and corrective actions, specified in Part 7 of the Accomplishment Instructions of Boeing Service Bulletin 747- 55A2050, Revision 2, dated January 23, 2015, except as required by paragraph (h)(3) of this AD, terminates the actions specified in paragraphs (i)(3)(i) and (i)(3)(ii) of this AD for the modified area only. \n\t(i) The repetitive inspections required by paragraph (g)(2) or (g)(3) of this AD, as applicable, only for Zone B, as specified in Part 4 of the Accomplishment Instructions of BoeingService Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(ii) The repetitive inspections required by paragraph (i) of AD 2006-10-16 for Zone B, as specified in Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\n(j) Repetitive Post-Modification Inspections and Corrective Actions \n\n\n\tAt the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015: Do the applicable inspections specified in paragraphs (j)(1) and (j)(2) of this AD, and all applicable corrective actions, in accordance with Part 8 of the Accomplishment Instructions of Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, except as required by paragraph (h)(3) of this AD. Do all applicable corrective actions before further flight. Repeat the applicable inspections at the applicable times specified in paragraph 1.E., ''Compliance,'' of Boeing Service Bulletin 747- 55A2050, Revision 2, dated January 23, 2015. \n\t(1) For Group 1 through 3 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, on which the Zone B modification specified in paragraph (i)(1) of this AD is done: Do non-destructive test (NDT) inspections (ultrasonic, high frequency eddy current, and low frequency eddy current inspections) or open-hole NDT inspections (high frequency eddy current inspections) of Zone B for cracking. \n\t(2) For Group 4 through 9 airplanes identified in Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, on which the Zone B modification specified in paragraph (i)(3) of this AD is done: Do open-hole NDT inspections (high frequency eddy current inspections) of Zone B for cracking. \n\n(k) Parts Installation Prohibition \n\n\n\tAs of the effective date of this AD, no person may install any Maraging or H-11 steel fasteners in the locations specified in this AD. Where Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015, specifies to install H-11 bolts (kept fasteners), this AD requires installation of Inconel bolts. \n\n(l) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in paragraph (m) of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. \n\t(3) An AMOC that provides an acceptable level ofsafety may be used for any repair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\t(4) AMOCs approved for AD 2006-10-16, are approved as AMOCs for the corresponding provisions of paragraph (g) of this AD, except for approved AMOCs that allow installation of Maraging or H-11 steel fasteners. \n\n(m) Related Information \n\n\n\tFor more information about this AD, contact Nathan Weigand, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6428; fax: 425-917-6590; email: nathan.p.weigand@faa.gov. \n\n(n) Material Incorporated by Reference \n\n\n\t(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. \n\t(i) Boeing Service Bulletin 747-55A2050, Revision 2, dated January 23, 2015. \n\t(ii) Reserved. \n\t(3) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone: 206-544- 5000, extension 1; fax: 206-766-5680; Internet https://www.myboeingfleet.com. \n\t(4) You may view this service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. \n\t(5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of thismaterial at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.