AD 2011-16-06

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires a general visual inspection for cracks and holes of the main equipment center (MEC) drip shields, and repairs if necessary; installation of a fiberglass reinforcing overcoat; and, for certain airplanes, installation of stiffening panels to the MEC drip shields. This AD was prompted by a report of a loss of bus control unit number 1 and generator control units numbers 1 and 2 while the airplane was on the ground, and multiple operator reports of cracked \n\n((Page 47428)) \n\nMEC drip shields. We are issuing this AD to prevent water penetration into the MEC, which could result in the loss of flight critical systems.

Final rule.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): \n\n2011-16-06 The Boeing Company: Amendment 39-16764; Docket No. FAA- 2011-0041; Directorate Identifier 2010-NM-227-AD. \n\nEffective Date \n\n\n\t(a) This AD is effective September 9, 2011. \n\nAffected ADs \n\n\n\t(b) None. \n\nApplicability \n\n\n\t(c) This AD applies to The Boeing Company Model 747-400 and - 400F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011. \n\nSubject \n\n\n\t(d) Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code25: Equipment/Furnishings. \n\nUnsafe Condition \n\n\n\t(e) This AD was prompted by a report of a loss of bus control unit number 1 and generator control units numbers 1 and 2 while the airplane was on the ground, and multiple operator reports of cracked main equipment center (MEC) drip shields. We are issuing this AD to prevent water penetration into the MEC, which could result in the loss of flight critical systems. \n\nCompliance \n\n\n\t(f) Comply with this AD within the compliance times specified, unless already done. \n\nInspection \n\n\n\t(g) Within 24 months after the effective date of this AD, do the actions specified in paragraph (g)(1) or (g)(2) of this AD, as applicable, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011. \n\t(1) For Group 1 and Group 3 airplanes, as identified in Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011: Do a general visual inspection of the MEC drip shield to detect cracking and holes, do all applicable repairs, and install the MEC drip shield panel stiffeners and the fiberglass reinforcing overcoat to the MEC drip shield, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011. Do all applicable repairs before further flight. \n\t(2) For Group 2 airplanes, as identified in Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011: Do a general visual inspection of the MEC drip shield to detect cracking and holes, do all applicable repairs, and install the fiberglass reinforcing overcoat to the MEC drip shield, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 25A3588, Revision 1, dated April 7, 2011. Do all applicable repairs before further flight. \n\n((Page 47430)) \n\nCredit for Actions Accomplished in Accordance With Previous Service Information \n\n\n\t(h) Accomplishing the actions required in paragraph (g) of this AD before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010, is considered acceptable for compliance with the corresponding actions specified in this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\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. 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 e-mailed 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\nRelated Information \n\n\n\t(j) For more information about this AD, contact Francis Smith, Aerospace Engineer, Cabin Safety & Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; phone: 425-917-6596 ; fax: 425-917-6590; e-mail: Francis.Smith@faa.gov. \n\nMaterial Incorporated by Reference \n\n\n\t(k) You must use Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011, to do the actions required by this AD, unless the AD specifies otherwise. \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\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; phone: 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. \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\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 the specified products. That NPRM published in the Federal Register on February 10, 2011 (76 FR 7513). The NPRM proposed a general visual inspection for cracks and holes of the main equipment center (MEC) drip shields, and repairs if necessary; installation of a fiberglass reinforcing overcoat; and, for certain airplanes, installation of stiffening panels to the MEC drip shields. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA's response to each comment. \n\nRequest To Reference Latest Service Bulletin Revision \n\n\n\tBoth UPS and Boeing requested that we revise the NPRM to require that actions be done in accordance with Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011. The NPRM referred to Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010, as the appropriate source of service information for the required actions. \n\tWe agree. Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011, removes airplane RT101 from this service information effectivity and provides operators with additional material options. The procedures remain unchanged. We revised paragraphs (c), (g), (g)(1), and (g)(2) in this final rule to refer to Boeing Alert Service Bulletin 747-25A3588, Revision 1, dated April 7, 2011. We added new paragraph (h) to the final rule to give credit for actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010, and re-identified subsequent paragraphs accordingly. \n\nRequest To Extend the Compliance Time \n\n\n\tUPS stated concern with Boeing's ability to provide adequate modification kits to all affected operators within the proposed 24- month compliance time. UPS justified its concern by stating that the NPRM acknowledges it would affect an estimated 41 airplanes of U.S. registry. UPS stated that worldwide, there are more than 150 Model 747- 400F airplanes that are affected by the referenced service information and many may attempt to accomplish this modification within the 24- month compliance time. At the time, Boeing had indicated it had materials available to produce only 6 kits, and will require 190 days lead time to replenish the stock. As the referenced service information specifies to install the parts provided in the kit by part number, an alternative method of compliance (AMOC) would be required for any operators needing to fabricate their own modification parts from raw materials, if Boeing is unable to provide the required modification kits in a timely basis for the proposed installation. \n\tWe infer that UPS is requesting that we extend the proposed compliance time. Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010; and Revision 1, dated April 7, 2011; were both coordinated between Boeing and the FAA. Proposed methods of compliance and the compliance time were weighed versus uncorrected risks in determining an acceptable and feasible corrective action. Boeing is most familiar with its ability to supply operators with instructions and kits to meet AD compliance, and determined it would be capable of reasonably achieving a 24-month compliance time with the proposed methods, when both Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010; and Revision 1, dated April 7, 2011; were drafted and approved. Although kits may not be available immediately for every airplane, Boeing has advised us that it is capable of creating and delivering additional kits for operators to use within the AD compliance time. \n\tOnce we issue this AD, any person may request approval of an AMOC under the provisions of paragraph (i) of this AD. We have not changed this AD in this regard. \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the change described previously. We also determined that this change will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 41 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n((Page 47429)) \n\n\n\n\n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Inspection and installation: 20 work-hours x $85 $1,109............... $2,809 $67,416 \n\tGroups 1, 3 (24 airplanes). per hour = $1,700. Inspection and installation: Group 17 work-hours x $85 Negligible........... 1,445 24,565 \n\t2 (17 airplanes). per hour = $1,445. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe estimate the following costs to do any necessary repairs that would be required based on the results of the inspection. We have no way of determining the number of aircraft that might need these repairs. \n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per airplane ---------------------------------------------------------------------------------------------------------------- Hole repair.......................... 1 work-hour x $85 per Negligible............. $85 per hole.hour = $85 per hole. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tAccording to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate. \n\nAuthority for This Rulemaking \n\n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in Subtitle VII, part A, subpart III, section 44701: ''General requirements.'' Under that section, Congress 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\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), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.