AD 2004-09-33

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 and 747-400D series airplanes, that requires a detailed inspection of the fire extinguishing system tube and clamp for correct installation or a repetitive pressure test of the fire extinguishing system tube for leakage, and corrective action, if necessary. This action is necessary to prevent a chafed hole in the fire extinguishing system tube of the aft cargo compartment, which could result in a lack of fire extinguishing agent and consequent uncontained fire in the aft cargo compartment. This action is intended to address the identified unsafe condition.

Final rule.

2004-09-33 Boeing: Amendment 39-13624. Docket 2003-NM-93-AD. \n\n\tApplicability: Model 747-400 and 747-400D series airplanes, as listed in Boeing Service Bulletin 747-26A2270, Revision 2, dated June 26, 2003; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent a chafed hole in the fire extinguishing system tube of the aft cargo compartment, which could result in a lack of fire extinguishing agent and consequent uncontained fire in the aft cargo compartment, accomplish the following: \n\nService Bulletin References \n\n\t(a) The term "service bulletin," as used in this AD, means the Accomplishment Instructions of Boeing Service Bulletin 747-26A2270, Revision 2, dated June 26, 2003. \n\nInspection/Pressure Test \n\n\t(b) Within 6,500 flight hours or 18 months after the effective date of this AD, whichever occurs first, perform the detailed inspection specified in paragraph (b)(1) of this AD or the pressure test specified in paragraph (b)(2) of this AD. \n\n\tNote 1: For the purposes of this AD, a detailed inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required." \n\n\t(1) Perform a detailed inspection of the fire extinguishing system tube and clamps for correct installation, either using an inspection hole and boroscope or with the floor panel removed, per the service bulletin. \n\n\t(i) If the fire extinguishing system tube is installed correctly, no further action is required by this AD. \n\n\t(ii) If the fire extinguishing system tube is installed incorrectly, prior to further flight, do the actions specified in paragraph (c) of this AD. \n\n\t(2) Perform a pressure test of the fire extinguishing system tube to check for leakage of the fire extinguishing agent per the service bulletin. \n\n\t(i) If leakage is not found, repeat the pressure test thereafter at intervals not to exceed 6,500 flight hours or 18 months, whichever occurs first, until the actions specified in paragraph (b)(1) or (c) of this AD have been done. \n\n\t(ii) If any leakage is found, prior to further flight, do the actions specified in paragraph (c) of this AD. \n\nRemoval and Installation/Repair/Replace \n\n\t(c) Remove the fire extinguishing system tube and do the actions in paragraph (c)(1) or (c)(2) of this AD, as applicable. \n\n\t(1) If, during the detailed inspection specified in paragraph (b)(1) of this AD, the fire extinguishing system tube was found to be installed incorrectly: Prior to further flight, perform a detailed inspection of the fire extinguishing system tube for chafing/damage per the service bulletin. \n\n\t(i) If no chafing/damage is found, prior to further flight, install the existing fire extinguishing system tube per Figure 3 of the service bulletin. \n\n\t(ii) If any chafing/damage is found, prior to further flight, replace the fire extinguishing system tube with a new tube or repair the fire extinguishing system tube, per the service bulletin, and install the new or repaired tube per Figure 3 of the service bulletin. \n\n\t(2) If, during the pressure test required by paragraph (b)(2) of this AD, leakage was found: Prior to further flight, replace the fire extinguishing system tube with a new tube or repair the fire extinguishing system tube, per the service bulletin, and install the new or repaired tube per Figure 3 of the service bulletin. \n\nTerminating Action \n\n\t(d) Accomplishment of the actions specified in paragraph (b)(1) or (c) of this AD constitutes terminating action for the requirements of this AD. \n\nActions Accomplished Per Previous Issue of Service Bulletin \n\n\t(e) Inspections, repetitive tests and corrective actions accomplished before the effective date of this AD per Boeing Alert Service Bulletin 747-26A2270, dated May 8, 2002; or Revision 1, dated January 16, 2003; are considered acceptable for compliance with the corresponding action specified in this AD. \n\nAlternative Methods of Compliance \n\n\t(f) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD. \n\nIncorporation by Reference \n\n\t(g) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-26A2270, Revision 2, dated June 26, 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(h) This amendment becomes effective on June 15, 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 and 747-400D series airplanes was published in the Federal Register on December 3, 2003 (68 FR 67616). That action proposed to require a detailed inspection of the fire extinguishing system tube and clamp for correct installation or a repetitive pressure test of the fire extinguishing system tube for leakage, and corrective action, if necessary. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received. \n\nRequest To Reference Latest Service Bulletin \n\n\tOne commenter requests that the notice of proposed rulemaking (NPRM) be revised to reference Boeing Service Bulletin 747-26A2270, Revision 2, dated June 26, 2003. The commenter notes that the NPRM refers to Revision 1 of that service bulletin as the appropriate source of service information for the proposed actions. \n\n\tThe FAA agrees. Since the issuance of the NPRM, we have reviewed and approved Revision 2 of the service bulletin. The inspection and corrective actions if necessary are essentially identical to those in Revision 1. Revision 2 revises the minimum tubing clearance in the Accomplishment Instructions for "Part 2--Tube removal and installation instructions" and Figure 3. No more work is necessary on airplanes changed by Revision 1. Therefore, we have revised this final rule to reference Revision 2 as the appropriate source of service information and revised paragraph (e) of this final rule to provide credit for accomplishing the required actions per Revision 1 before the effective date of this AD. \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption ofthe rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 416 airplanes of the affected design in the worldwide fleet. The FAA estimates that 44 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required inspection or pressure test, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $2,860, or $65 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 performthe 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 thecriteria 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\nAccordingly, 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\n§ 39.13 (Amended) \n\n2. Section 39.13 is amended by adding the following new airworthiness directive: