AD 2004-22-04

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400, -400D, and -400F series airplanes, equipped with GE or P&W series engines. This amendment requires modifications and functional tests of the wiring of the wire integration unit and the air supply control test unit (ASCTU) of the engine bleed air distribution system. The actions specified by this AD are intended to prevent inadvertent commanded shutdown of the engine bleed air distribution systems due to an erroneous ASCTU command. This type of shutdown could cause depressurization of the airplane and subsequent ice build-up on the engine inlets during descent, which could result in ingestion of ice into the engine(s) and consequent loss of thrust on one or more engines. This action is intended to address the identified unsafe condition.

Final rule.

2004-22-04 Boeing: Amendment 39-13832. Docket 2002-NM-173-AD. \n\n\tApplicability: Model 747-400, -400D, and -400F series airplanes; as listed in Boeing Service Bulletin 747-36A2136, Revision 2, dated May 13, 2004; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent inadvertent commanded shutdown of the engine bleed air distribution systems due to an erroneous air supply control test unit (ASCTU) command, which could cause depressurization of the airplane and subsequent ice build-up on the engine inlets during descent, which could result in ingestion of ice into the engine(s) and consequent loss of thrust on one or more engines; accomplish the following: \n\nModifications/Tests \n\n\t(a) Within 18 months after the effective date of this AD: Do the modifications and functional tests of the wiring of the wire integration unit (WIU) and the ASCTU of the engine bleed air distribution system specified in paragraphs (a)(1), (a)(2), (a)(3), and (a)(4) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-36A2136, Revision 2, dated May 13, 2004. Before further flight after accomplishing paragraphs (a)(2), (a)(3), and (a)(4) of this AD: Do the post- installation tests in accordance with the service bulletin. \n\n\t(1) Remove the existing ASCTU. \n\n\t(2) Do the wiring changes between the WIU and ASCTU and the wiring changes to the WIU. \n\n\t(3) Do the resistance tests. \n\n\t(4) Install a new or reworked ASCTU. \n\nCredit for Previous Issues of Boeing Service Bulletin \n\n\t(b) Modifications and tests accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-36A2136, dated April 12, 2001; or Revision 1, dated January 17, 2002; are considered acceptable for compliance with the corresponding actions specified in paragraph (a) of this AD, if the resistance tests were done with the ASCTU removed. If the resistance tests were done withthe ASCTU installed, do the actions specified in paragraphs (b)(1), (b)(2), and (b)(3) of this AD, at the time specified in paragraph (a) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-36A2136, Revision 2, dated May 13, 2004. Before further flight after accomplishing paragraph (b)(3) of this AD: Do the post-installation tests in accordance with the service bulletin. \n\n\t(1) Remove the existing ASCTU. \n\n\t(2) Do the resistance tests. \n\n\t(3) Reinstall the ASCTU. \n\nPart Installation \n\n\t(c) As of the effective date of this AD, no person may install on any airplane an ASCTU having a part number listed in the "Old Part Number" column in the table specified in paragraph 3.C. of the Accomplishment Instructions of Hamilton Sundstrand Service Bulletin 36-186, dated March 30, 2001. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(d) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, ifrequested in accordance with the procedures found in 14 CFR 39.19. \n\nIncorporation by Reference \n\n\t(e) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-36A2136, Revision 2, dated May 13, 2004. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 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 . \n\nEffective Date \n\n\t(f) This amendment becomes effective on December 2, 2004.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747-400, - 400D, and -400F series airplanes, equipped with GE or P&W series engines, was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on August 16, 2004 (69 FR 50341). That action proposed to require modifications and functional tests of the wiring of the wire integration unit and the air supply control test unit of the engine bleed air distribution system. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. \n\nConclusion \n\n\tThe FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately414 airplanes of the affected design in the worldwide fleet. The FAA estimates that 70 airplanes of U.S. registry will be affected by this AD, that it will take approximately 8 work hours per airplane to accomplish the required actions, and that the average labor rate is $65 per work hour. Required parts will be minimal. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $36,400, or $520 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \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\n Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive: