AD 97-26-07

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires a one-time inspection to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, that AD also requires an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. This amendment requires repetitive inspections in lieu of the one-time inspection. This amendment also expands the applicability of the existing AD. This amendment is prompted by reports of chafing of the sleeving. The actions specified in this AD are intended to detect and correct abrasion of the Teflon sleeving and wires in the bundles ofthe fuel boost pumps for the numbers 1 and 4 main fuel tanks and of the auxiliary tank jettison pumps (if installed), which could result in electrical arcing between the wires and the aluminum conduit and consequent fire or explosion of the fuel tank.

Final rule; request for comments

97-26-07 BOEING: Amendment 39-10250. Docket 97-NM-295-AD. Supersedes AD 96-26-06, Amendment 39-9870. \n\n\tApplicability: All Model 747 series airplanes, certificated in any category.\n \n\tNOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (h) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo detect and correct abrasion of the Teflon sleeving and wires in the bundles of the fuel boost pumps for the numbers 1 and 4 main fuel tanks and of the auxiliary tank jettison pumps (if installed), which could result in electrical arcing between the wires and the aluminum conduit and consequent fire or explosion of the fuel tank, accomplish the following: \n\n\t(a)\tPerform an initial inspection to detect damage of the sleeving and wire bundles of the forward and aft boost pumps of the numbers 1 and 4 main fuel tanks, and of the wire bundles of the auxiliary tank jettison pumps (if installed), in accordance with Boeing Alert Service Bulletin 747-28A2204, dated December 19, 1996, or Boeing Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997, at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. \n\n\t\t(1)\tFor airplanes having line numbers 001 through 432 inclusive: Inspect within 120 days after January 21, 1997 (the effective date of AD 96-26-06, amendment 39-9870).\n\n\t\t(2)\tFor airplanes having line numbers 433 and subsequent: Inspect at the later of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. \n\n\t\t\t(i)\tPrior to the accumulation of 20,000 flight cycles or 60,000 flight hours, whichever occurs first; or \n\n\t\t\t(ii)\tWithin 120 days after the effective date of this AD. \n\t(b)\tRepeat the inspection required by paragraph (a) of this AD at intervals not to exceed 20,000 flight cycles or 60,000 flight hours since the last inspection, whichever occurs first.\n\n\t(c)\tIf any damaged sleeving is found, prior to further flight, replace the sleeving with new sleeving in accordance with Boeing Alert Service Bulletin 747-28A2204, dated December 19, 1996, or Boeing Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997. \n\n\t(d)\tIf any damaged wire is found, prior to further flight, repair or replace the wire with a new wire in accordance with Boeing Alert Service Bulletin 747-28A2204, dated December 19, 1996, or Boeing Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997. \n\n\t(e)\tIf any burned wire is found, prior to further flight, perform an inspection to detect damage of the conduit, in accordance with Boeing Alert Service Bulletin 747-28A2204, dated December 19, 1996, or Boeing Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997. If any damage is found, prior to further flight, replace the conduit with a serviceable conduit in accordance with either of the service bulletins. After the effective date of this AD, only Revision 1 of this service bulletin shall be used. \n\n\t(f)\tFor airplanes having line numbers 433 and subsequent: Within 14 days after accomplishing the initial inspection required by paragraph (a) of this AD, submit a report of any damaged sleeving (i.e., holes, breaks, cuts, splits), damaged wire (i.e., worn or cracked insulation, exposed conductor, indication of arcing/burning), or damaged conduit to the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, WA 98055-4056; fax (425) 227-1181. The report shall include the information specified in paragraphs (f)(1), (f)(2), (f)(3), (f)(4), and (f)(5) of this AD. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. \n\t\t(1)\tThe airplane serial number. \n\t\t(2)\tThe total hours time-in-service accumulated on the airplane. \n\t\t(3)\tThe total number of flight cycles accumulated on the airplane. \n\t\t(4)\tA description of any damage found. \n\t\t(5)\tThe location of where the damaged part was installed. \n\n\t(g)\tFor airplanes having line numbers 433 and subsequent: Within 14 days after accomplishing the initial inspection required by paragraph (a) of this AD, submit any damaged part to the Manager, Seattle ACO. The damaged part shall be tagged to include the information specified in paragraphs (f)(1), (f)(2), (f)(3), (f)(4), and (f)(5) of this AD. Additionally, operators shall align the inner sleeving, outer sleeving, and wire as installed in the airplane, and secure the sleeving and wiring in place by taping or other means when submitting the damaged part to the Manager, Seattle ACO. Information collection requirements contained in this regulation have been approved by the OMB under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. \n\n\t(h)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\tNOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\t(i)\tSpecial flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(j)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 747- 28A2204, dated December 19, 1996, or Boeing Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997. \n\n\t\t(1)\tThe incorporation by reference of Boeing Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997, is approved by the Director of the Federal Register. \n\n\t\t(2)\tThis incorporation by reference of Boeing Alert Service Bulletin 747-28A2204, dated December 19, 1996, was approved previously by the Director of the Federal Register as of January 21, 1997 (62 FR 304, January 3, 1997). \n\n\t\t(3)\tCopies may beobtained 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 Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(k)\tThis amendment becomes effective on December 29, 1997.

On December 23, 1996, the FAA issued AD 96-26-06, amendment 39-9870 (62 FR 304, January 3, 1997), applicable to certain Boeing Model 747 series airplanes, to require a one-time inspection to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, that AD also requires an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. That action was prompted by an FAA determination that an environment conducive to vibration exists in the conduit and wire bundles of the boost pumps and of the auxiliary tank jettison pumps, which can cause abrasion of the Teflon sleeving and consequent abrasion of the wires in the bundles. The actions required by that AD are intended to detect and correct such abrasion, which could result in electrical arcing between the wires and the aluminum conduit and consequent fire or explosion of the fuel tank. \n\nActions Since Issuance of Previous Rule \n\n\tSince the issuance of AD 96-26-06, the FAA has received numerous reports of chafing through the outer Teflon sleeve of the wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks. Several of the sleeves had large holes. No cases of wire chafing through the insulation to the conductor were reported. Investigation revealed that two of the affected operators had varying levels of chafing with damage on 48 percent of their airplanes. Both of these operators had replaced the aluminum conduits with stainless steel conduits. Other affected operators' airplanes (with flight hour totals similar to those of the airplanes discussed previously) that were equipped with aluminum conduits had a much lower incidence of reported damage.At the time of issuance of AD 96-26-06, the FAA considered the aluminum conduit to be more susceptible to chafing and burning as a result of electrical arcing between the wires and the aluminum conduit than the stainless steel conduit. Therefore, the FAA limited the inspection required by AD 96-26-06 to Boeing Model 747 series airplanes equipped with aluminum conduits (line numbers 001 through 432 inclusive). \n\n\tIn light of these new findings, the FAA has determined that Boeing Model 747 series airplanes equipped with stainless steel conduits are subject to the same unsafe condition addressed in AD 96-26-06. In addition, the FAA finds that, regardless of the conduit material, repetitive inspections are necessary to determine if the sleeving of the wire bundles continues to provide a protective barrier after extended time in service. \n\nExplanation of Relevant Service Information \n\n\tAdditionally, since the issuance of AD 96-26-06, the FAA has reviewed and approved Revision 1of Boeing Service Bulletin 747-28A2204, dated October 30, 1997. Revision 1 of the service bulletin revises the effectivity listing of the original version of the service bulletin (which was referenced in AD 96-26-06 as the appropriate source of service information) by adding Boeing Model 747 series airplanes having line numbers 433 through 1120 inclusive. The inspection and corrective procedures described in Revision 1 are essentially identical to those described in the original version of the alert service bulletin. \n\nExplanation of Requirements of Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this AD supersedes AD 96-26-06 to require repetitive inspections, in lieu of the previously required one-time inspection, to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement ofany damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, this AD also continues to require an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. This AD also expands the applicability of the existing AD to include additional airplanes. This AD requires that operators submit a report to the FAA of any damage found as a result of the initial inspection.\n\nDifferences Between the AD and the Relevant Service Information \n\n\tOperators should note that the applicability of the AD differs from the effectivity listing of Revision 1 of the referenced service bulletin. The FAA has determined that all Boeing Model 747 series airplanes are subject to the addressed unsafe condition. \n\nInterim Action \n\n\tThis is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking. \n\nDetermination of Rule's Effective Date \n\n\tSince a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 97-NM-295-AD." The postcard will be date stamped and returned to the commenter. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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\n PART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by removing amendment 39-9870 (62 FR 304, January 3, 1997), and by adding a new airworthiness directive (AD), amendment 39-10250, to read as follows: