AD 2009-22-14

We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-200C and 747-200F series airplanes. This AD requires installing larger moisture shrouds and additional drain lines in the electrical/electronic equipment center. This AD results from reports of water contamination in the electrical/electronic units in the main equipment center. We are issuing this AD to prevent water contamination in the electrical/electronic units in the main equipment center, which could result in an electrical short and potential loss of several functions essential for safe flight.

Final rule.

2009-22-14 Boeing: Amendment 39-16067. Docket No. FAA-2008-1362; Directorate Identifier 2008-NM-150-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective December 8, 2009. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to Boeing Model 747-200C and 747-200F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008. \n\nUnsafe Condition \n\n\t(d) This AD results from reports of water contamination in the electrical/electronic units in the main equipment center. We are issuing this AD to prevent water contamination in the electrical/ electronic units in the main equipment center, which could result in an electrical short and potential loss of several functions essential for safe flight. \n\nCompliance \n\n\t(e) Comply with this AD within the compliance times specified, unless already done. \n\nInstallation of Shrouds and Drain Lines \n\n\t(f) Within 72 months after theeffective date of this AD, install larger moisture shrouds and additional drain lines, by doing all the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008. \n\nInstallation of Moisture Curtains \n\n\t(g) Prior to or concurrently with accomplishing the actions required by paragraph (f) of this AD: Install protective moisture curtains in the main equipment center in accordance with Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008. \n\n\tNote 1: The installation required by paragraph (g) of this AD is the same installation required by paragraph (f) of AD 2007-26-03, amendment 39-15305, for Boeing Model 747-200C and -200F series airplanes (AD 2007-26-03 specifies that the actions be done in accordance with Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007). Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008, which affects Boeing Model 747-200F airplanes,variable numbers RR566 and RR551 through RR556 inclusive, is an alternative method of compliance for the requirements of paragraph (g) of AD 2007-26-03. Airplanes identified as Group 1, Group 3, and Group 6 airplanes in Boeing Service Bulletin 747- 25A3430, Revision 1, dated October 9, 2008, must comply with paragraph (g) of AD 2007-26-03. \n\nInstallations Accomplished According to Previous Issue of Service Bulletin \n\n\t(h) Installations accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007, are considered acceptable for compliance with the corresponding action, paragraph (g) of this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(i)(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: Marcia Smith, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6484; fax (425) 917-6590. Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \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\nMaterial Incorporated by Reference \n\n\t(j) You must use Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008; and Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008; as applicable; to do the actions required by this AD, unless the AD specifies otherwise. \n\t(1) The Director ofthe Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. \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\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 or 425-227-1152. \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\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 747-200C and 747-200F series airplanes. That NPRM was published in the Federal Register on January 12, 2009 (74 FR 1158). That NPRM proposed to require installing larger moisture shrouds and additional drain lines in the electrical/electronic equipment center. \n\nActions Since NPRM Was Issued \n\n\tParagraph (g) of the NPRM cited Boeing Alert Service Bulletin 747- 25A3430, dated February 15, 2007, as the appropriate source of service information for the prior or concurrent action for the proposed installation; Boeing has revised this service bulletin. Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008, moves certain airplanes to new groups 5 and 6, and adds respective weight and balance tables, materials, parts, and work instructions and figures, but does not add any new procedures. We have revised paragraph (g) of the final rule to refer to Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008, and added new paragraph (h) to this AD to give credit for accomplishing the original service bulletin before the effective date of this AD. We have re-identified subsequent paragraphs accordingly. We have also revised Note 1 of this AD to refer to Revision 1. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comments received from the two commenters. \n\nRequest for Terminology Clarification \n\n\tBoeing requests that we change the phrase "reworking the base line (BL) 11 intercostals'' found in the Relevant Service Information section to "reworking the butt line (BL) 11 intercostals.'' Boeing recommends using standard aerospace terminology for geometric dimensioning. \n\tWe partially agree. The language Boeing proposes is the correct terminology, but the Relevant Service Informationsection in the NPRM is not repeated in the final rule. We have not changed the AD in this regard. \n\nRequest To Change Affected Airplanes \n\n\tBoeing requests that we revise the Costs of Compliance section of the NPRM to change the number of affected U.S. airplanes from 25 to 31. Current analysis of the Boeing Airplane Configuration Tracking System airplane database indicates 31 airplanes are affected. \n\tWe agree, for the reason explained by the commenter. We have revised this final rule accordingly. \n\nRequest for No Requirement of Re-Installation of Curtains \n\n\tNorthwest Airlines (Northwest) requests that we consider not requiring re-installation of curtains after accomplishing shroud installation per the instructions of Boeing Alert Service Bulletin 747- 25A3431, dated March 6, 2008. Northwest explains that since 2001, it has operated two 747 freighters with the extended overhead moisture shrouds (similar to those installed per Boeing Alert Service Bulletin 747-25A3431, datedMarch 6, 2008) that had been installed during a passenger-to-freighter conversion but did not have the curtains installed. Northwest explains that service experience on the two airplanes showed that there were no moisture ingress problems. \n\tWe disagree with the request. While Northwest may not have experienced moisture ingress problems on its two airplanes that have been operating without curtains, we cannot mandate fleet-wide action on data from two airplanes. The AD is intended to prevent water contamination in the electrical/electronic main equipment center of the fleet. However, under the provisions of paragraph (i) of this AD, Northwest may request an alternative method of compliance if it can provide data that substantiate the request. We have not changed this AD in this regard. \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously.We also determined that the changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\tWe estimate that this proposed AD would affect 31 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. \n\n\tEstimated Costs \n\n\nAction\nWork hours\nAverage labor rate per hour\nParts\nCost per product\nNumber of U.S.-registered airplanes\nFleet cost\nInstallations\nUp to 75\n$80\nUp to $28,405\n Up to $34,405\n31\nUp to $1,066,555\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\tWe are issuing this rulemaking under the authority described in "Subtitle VII, Part A, Subpart III, Section 44701: Generalrequirements.'' 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\tThis AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a "significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and \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\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \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 FAA amends Sec. 39.13 by adding the following new AD: