AD 2004-20-16

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-200B, -200C, -200F, -300, -400, -400D, and -400F series airplanes; and Model 747SP series airplanes, that requires repetitive functional tests of the auxiliary power unit (APU) and engine fire shutoff switches and repetitive replacements of the APU and engine fire shutoff switches. The AD also provides an optional terminating action for the repetitive functional tests and replacements. This action is necessary to prevent mineral build-up on the APU and engine fire shutoff switches, which could lead to failure of the switches to discharge fire suppressant in the affected area and could result in an uncontrolled fire that could spread to the strut, wing, or aft body of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2004-20-16 Boeing: Amendment 39-13821. Docket 2002-NM-286-AD. \n\n\tApplicability: Model 747-200B, -200C, -200F, -300, -400, -400D, and -400F series airplanes; and Model 747SP series airplanes; as listed in Boeing Alert Service Bulletin 747-26A2274, Revision 1, dated January 9, 2003; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent mineral build-up on the auxiliary power unit (APU) and engine fire shutoff switches, which could lead to failure of the switches to discharge fire suppressant in the affected area and could result in an uncontrolled fire that could spread to the strut, wing, or aft body of the airplane, accomplish the following: \n\nService Bulletin Reference \n\n\t(a) The term "service bulletin," as used in this AD, means the Accomplishment Instructions of Boeing Alert Service Bulletin 747-26A2274, Revision 1, dated January 9, 2003. \n\nInitial and Repetitive Functional Test \n\n\t(b) At the later of the compliance times specified in paragraphs (b)(1) and (b)(2) of this AD, perform a functional test of the APU and engine fire shutoff switches, in accordance with the service bulletin. Repeat the functional test thereafter at intervals not to exceed 18 months. \n\n\t(1) Within 18 months since the date of issuance of the original Airworthiness Certificate or the original Export Certificate of Airworthiness. \n\n\t(2) Within 90 days after the effective date of this AD. \n\nFire Shutoff Switch Failure \n\n\t(c) If any fire shutoff switch fails during any functional test required by paragraph (b) or (f) of this AD, before further flight, replace the switch with a new or serviceable switch, in accordance with the service bulletin. Repeat the switch replacement thereafter at intervals not to exceed 36 months. \n\nReplacement \n\n\t(d) Within 36 months after the effective date of this AD, replace all APU and engine fire shutoff switches that have not been previously replaced per paragraph (c) of thisAD with new or serviceable switches, in accordance with the service bulletin. Repeat the switch replacement thereafter at intervals not to exceed 36 months. \n\nDeactivation of Lucas Humidifier \n\n\t(e) Operators may terminate the repetitive requirements of paragraphs (b), (c), and (d) of this AD by accomplishing the actions in paragraphs (e)(1) and (e)(2) of this AD, except as provided by paragraph (f) of this AD. \n\n\t(1) Deactivate the Lucas humidifier, part number (P/N) M01AA0101, M01AB0101, M01AB0102, or M01AB0103, in accordance with the service bulletin. \n\n\t(2) Before further flight following the deactivation specified in paragraph (e)(1) of this AD, replace all APU and engine fire shutoff switches with new or serviceable switches in accordance with the service bulletin. \n\nReactivation of Lucas Humidifier \n\n\t(f) For any airplanes on which Lucas humidifier, P/N M01AA0101, M01AB0101, M01AB0102, or M01AB0103 is reactivated after the effective date of this AD: Do the requirements of paragraphs (f)(1) and (f)(2) of this AD at the times specified in those paragraphs. \n\n\t(1) Within 18 months after reactivating the humidifier, and thereafter at intervals not to exceed 18 months, do the functional test required by paragraph (b) of this AD. \n\n\t(2) Within 36 months after reactivating the humidifier, and thereafter at intervals not to exceed 36 months, replace all APU and engine fire shutoff switches that have not been previously replaced per paragraph (c) of this AD. Do the replacements per paragraph (d) of this AD. \n\nActions Accomplished Per Previous Issue of Service Bulletin \n\n\t(g) Unless otherwise specified in this AD, actions accomplished before the effective date of this AD per Boeing Alert Service Bulletin 747-26A2274, dated August 29, 2002, are considered acceptable for compliance with the corresponding action specified in this AD. \n\nAlternative Methods of Compliance \n\n\t(h) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD. \n\nIncorporation by Reference \n\n\t(i) The actions shall be done in accordance with Boeing Alert Service Bulletin 747-26A2274, Revision 1, dated January 9, 2003. 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 Airplanes, 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(j) This amendment becomes effective on November 17, 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 747-200B, -200C, -200F, -300, -400, -400D, and -400F series airplanes; and Model 747SP series airplanes, was published in the Federal Register on June 23, 2004 (69 FR 34971). That action proposed to require repetitive functional tests of the auxiliary power unit (APU) and engine fire shutoff switches and repetitive replacements of the APU and engine fire shutoff switches. That action also proposed to provide an optional terminating action for the repetitive functional tests and replacements. \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\nClarification of Summary Language \n\n\tSince the proposed AD was published we noticed that in the Summary of the proposed AD we referred to "inspections" instead of "functional tests." We have corrected the Summary of this AD. \n\nCost Impact \n\n\tThere are approximately 316 airplanes of the affected design in the worldwide fleet. We estimate that 50 airplanes of U.S. registry will be affected by this AD, and that the average labor rate is $65 per work hour. Table 1 provides the estimated costs for U.S. operators to comply with this AD. \n\nTable 1.-Estimated Costs\n\n\nAction\nWork hours\nCost per airplane\nTotal cost\nInspection and Functional Test (per test cycle)\n10-14 (depending on airplane model)\n$650-910\n$32,500-45,500\n\n\tThe cost impact figures discussed above are 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 thefuture 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\tAccordingly, 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\n\t1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: