AD 98-10-10 ACTIVE

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 and 767 series airplanes. This action requires a one-time inspection to confirm the installation of Teflon sleeves over certain electrical wires inside conduits installed in the fuel tanks; and corrective actions, if necessary. This amendment is prompted by a report of missing Teflon sleeves, which protect the wiring insulation from chafing. The actions specified in this AD are intended to prevent such chafing, which could eventually expose the electrical conductor creating the potential for arcing from the wire to the conduit, and consequent fuel tank fire/explosion.

Final rule; request for comments

98-10-10 BOEING: Amendment 39-10522. Docket 98-NM-111-AD. \n\n\tApplicability: Model 747 series airplanes, line positions 0001 through 1145 inclusive, that have not been inspected in accordance with AD 96-26-06, amendment 39-9870 (reference Boeing Alert Service Bulletin 747-28A2204, dated December 19, 1996), or AD 97-26-07, amendment 39-10250 (reference Boeing Alert Service Bulletin 747-28A2204, Revision 1, dated October 30, 1997); and Model 767 series airplanes, line positions 001 through 689 inclusive, and 691; 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 withparagraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent chafing of the wire insulation inside conduits installed in the fuel tanks, which could eventually expose the electrical conductor creating the potential for arcing from the wire to the conduit, and consequent fuel tank fire/explosion, accomplish the following: \n\n\t(a)\tWithin 60 days after the effective date of this AD, perform a one-time visual inspection to confirm installation of Teflon sleeves over the electrical wires to the boost pumps installed inside conduits in the numbers 1 and 4 main fuel tanks (for Model 747 series airplanes), or in the main and center wing tanks (for Model 767 series airplanes), as applicable, in accordance with Boeing Message M-7200-98-01080, dated March 18, 1998. \n\n\t(b)\tIf any Teflon sleeve is found to be missing during the inspection required by paragraph (a) of this AD, prior to further flight, inspect to detect damage to the wires, in accordance with Boeing Message M-7200-98-01080, dated March 18, 1998. \n\n\t\t(1)\tIf no damage is found, prior to further flight, install a Teflon sleeve in accordance with the message. \n\n\t\t(2)\tIf any damage is found, prior to further flight, inspect to detect damage to the conduits in accordance with the message. \n\n\t\t\t(i)\tIf no damage is found, prior to further flight, replace any damaged wire and install a Teflon sleeve in accordance with the message. \n\n\t\t\t(ii)\tIf any damage is found, prior to further flight, replace any damaged wire and conduit and install a Teflon sleeve, in accordance with the message. \n\n\tNOTE 2: Boeing Message M-7200-98-01080, dated March 18, 1998, refers to Boeing Alert Service Bulletin 747-28A2204 as an additional source of service information. \n\n\t(c)\tWithin 10 days after finding any damage during any inspection required by paragraph (b) of this AD, send damaged wiring and conduits and submit a report to the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-1181. The report must include the following: \n\n\tthe airplane model number; \n\tthe airplane line position; \n\tthe total number of hours time-in-service accumulated on the airplane; \n\tthe total number of flight cycles accumulated on the airplane; \n\ta description of the area of the wiring where the sleeving was missing; and \n\ta description of the damage found. \n\nInformation 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(d)\tAn alternative method of compliance or adjustment of the compliancetime 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 3: 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(e)\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(f)\tThe actions shall be done in accordance with Boeing Message M-7200-98-01080, dated March 18, 1998. 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 Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(g)\tThis amendment becomes effective on May 27, 1998.

On July 17, 1996, shortly after takeoff from John F. Kennedy International Airport in Jamaica, New York, a Boeing Model 747 series airplane was involved in an accident during which the center fuel tank exploded. Ensuing investigations of the cause of the accident have focused on the fuel tank explosion. \n\n\tA recent inspection of the main fuel tanks on a Model 747 series airplane indicated that the inner and outer Teflon sleeves were missing from wiring within the conduit of the aft boost pump to the number 4 main fuel tank. The reason for the missing sleeves has not been determined. Missing Teflon sleeves could result in chafing of the wire insulation encasing the fuel pump wiring. These conditions, if not corrected, could eventually expose the electrical conductor creating the potential for arcing from the wire to the conduit, and consequent fuel tank fire/explosion. \n\nSimilar Airplanes \n\n\tThe vibration environment and the conduit and wiring installations associated with fuel pumps in the wing fuel tanks of Model 747 and 767 series airplanes are similar. Therefore, the FAA has determined that both models may be subject to the unsafe condition identified in this AD.\n\nRelated AD's \n\n\tThe FAA has issued a number of AD's to address various fuel-tank related unsafe conditions on Boeing Model 747 series airplanes, including the following: \n\n\t AD 79-05-04, amendment 39-3431 (44 FR 12636, March 8, 1979). This AD was prompted by a report indicating that fuel pump wires had chafed through the insulation in an aluminum conduit inside an auxiliary fuel tank on a Model 747 series airplane. Electrical arcing from the chafed wire to the aluminum conduit had burned a hole in the conduit permitting fuel leakage; however, the arcing did not result in a fire or explosion. That AD requires discontinued use of the auxiliary fuel tanks unless Teflon sleeving is installed over the wire bundles in accordance with Boeing Alert Service Bulletin 747-28A2091, Revision 1, dated February 5, 1979. \n\n\t AD 79-06-02, amendment 39-3439 (44 FR 16362, March 19, 1979). Because the conduit and wiring installations for the auxiliary fuel tanks are similar to those of the number 1 and number 4 main fuel tanks on Model 747 series airplanes, an inspection of the boost pump wiring of the main fuel tank was conducted on other airplanes of this model. Although none of the wires inspected had worn completely through the insulation, chafing through 80 percent of the total insulation thickness was found on numerous wires. The reported chafing was attributed to vibration of the wires against the conduit wall. Based on these results, AD 79-26-02 was issued to require inspection, repair, and modification of the boost pump wires of the outboard main (number 1 and number 4) fuel tanks on Model 747 series airplanes. Corrective actions involve replacing chafed wires, installing wire ties at equal intervals, and installing double-layer Teflon sleeves over the wires, in accordance with Boeing Alert Service Bulletin 747-28A2092, dated February 12, 1979. \n\n\t AD 96-26-06, amendment 39-9870 (62 FR 304, January 1, 1997). Following the 1996 accident, AD 96-26-06 was issued to require a one-time inspection in accordance with Boeing Alert Service Bulletin 747-28A2201, dated December 19, 1996. The purpose of this inspection was to detect damage to the Teflon sleeving and wire bundles to the forward and aft boost pumps for the number 1 and number 4 main fuel tanks and to the auxiliary tank jettison pumps (if installed) on Model 747 series airplanes equipped with aluminum conduits. At the time AD 96-26-06 was issued, the FAA had determined that sleeving inside aluminum conduits was more susceptible to chafing and burn-through in the event of arcing than sleeving inside stainless steel conduits. \n\n\t AD 97-26-07, amendment 39-10250 (62 FR 65352, December 12, 1997). Based on damage reports from two operators that had replaced thealuminum conduits with stainless steel conduits and had found significant chafing on 48 percent of the airplanes checked, the FAA concluded that stainless steel conduit installations also should be inspected. Therefore, the FAA issued AD 97-26-07, which supersedes AD 96-26-06 to expand the inspection requirements to include Model 747 series airplanes having stainless steel conduits, and to add repetitive inspections of the Teflon sleeving on all Model 747 series airplanes to determine whether the sleeving would continue to provide a protective barrier after extended time in service. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Message M-7200-98-01080, dated March 18, 1998 (hereinafter referred to as the "message"). The message describes procedures for a one-time inspection to confirm installation of Teflon sleeving over wiring in conduits in the boost pumps of the numbers 1 and 4 main fuel tanks on Boeing Model 747 series airplanes, and in the main and center wing tanks on Model 767 series airplanes; and corrective actions, if necessary. The corrective actions involve follow-on inspections, installation of Teflon sleeves, and replacement of damaged wiring and conduits. Accomplishment of the actions specified in the message is intended to adequately address the identified unsafe condition. \n\n\tThe message refers to Boeing Alert Service Bulletin 747-28A2204 as an additional source of service information for accomplishment of the requirements of this AD. \n\nExplanation of the Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent chafing of electrical wiring inside the conduits, which could eventually expose the electrical conductor creating the potential for arcing from the wire to the conduit, and consequent fuel tank fire/explosion. This AD requires accomplishment of the actionsspecified in the message described previously, except as described below. This AD also requires operators to send any damaged wires and conduits, and to submit a report to the FAA. \n\nDifferences Between the Rule and the Message \n\n\tOperators should note that, whereas the message provides a compliance time of 30 days, the rule requires compliance within 60 days. Although the message recommends a 30-day compliance time, the manufacturer, through a subsequent review of the number of affected airplanes, has advised the FAA that 30 days will be insufficient to accomplish the actions required by this AD on such a large fleet. The FAA has determined that a 60-day compliance time is appropriate in consideration of the safety implications of this AD, the size of the affected fleet, and the practical aspects of an orderly inspection within the allotted time. \n\nDetermination of Rule's Effective Date \n\n\tSince a situation exists that requires the immediate adoption of this regulation, itis 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 determiningwhether 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 98-NM-111-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 thedistribution 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 adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA),\nTransport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-111-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.\n\n\tThe service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined 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.

Ed Hormel, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2681; fax (425) 227-1181.