AD 98-07-26

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 767 series airplanes. This action requires a detailed visual inspection(s) for damage or chafing of certain electrical wire bundles and for clearance between the wire bundles and adjacent forward galley air chiller; and follow-on corrective actions. This amendment is prompted by a report indicating that damaged wires caused the tripping of electrical circuit breakers and the display of caution messages by the engine indication and crew alerting system. The actions specified in this AD are intended to prevent failure of essential electrical systems and a potential fire hazard for passengers and crewmembers, due to damage or chafing of the wire bundles that resulted in arcing between exposed conductors and burning of the adjacent electrical bundles.

Final rule; request for comments.

98-07-26 BOEING: Amendment 39-10448. Docket 98-NM-95-AD.\n\n\tApplicability: Model 767 series airplanes, line numbers 1 through 683 inclusive, equipped with forward galley air chillers; 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 (b) 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 prevent arcing between exposed conductors, which could result in burning of the adjacent electrical bundles, failure of essential electrical systems, and consequent fire hazard for passengers and crewmembers, accomplish the following:\n\n\t(a)\tWithin 30 days after the effective date of this AD, perform a detailed visual inspection for damage or chafing of the electrical wiring bundles located forward of the P37 panel adjacent to the AE0218 disconnect panel, and for adequate clearance between the wire bundles and adjacent forward galley air chiller, in accordance with Boeing Message Number M-7200-98-00140, dated January 11, 1998.\n\n\tNOTE 2: Boeing Message Number M-7200-98-00140, dated January 11, 1998, also\nreferences Boeing Standard Wiring Practices Manual D6-54446, as an additional source of service information.\n\n\t\t(1)\tIf no damage or chafing is detected and adequate clearance exists, accomplish either paragraph (a)(1)(i) or (a)(1)(ii) of thisAD. \n\n\t\t\t(i)\tRepeat the visual inspection required by paragraph (a) of this AD, thereafter, each time the forward galley air chiller is removed and reinstalled. Or \n\n\t\t\t(ii)\tPrior to further flight, install protective tape or sleeve over the wire bundles in accordance with Section 20-10-11 of the Boeing Standard Wiring Practices Manual. Operators shall use one of the following materials to protect the bundles: RT876 (sleeve), TFE-2X standard wall thickness (sleeve), P-440 (tape), Scotch 70 (tape), or CHR-A-2005 (tape).\n\n\t\t(2)\tIf no damage or chafing is detected and inadequate clearance exists, prior to further flight, modify the routing of the wire bundles in accordance with the Boeing message, and install protective tape or sleeve over the wire bundles in accordance with Section 20-10-11 of the Boeing Standard Wiring Practices Manual. Operators shall use one of the following materials to protect the bundles: RT876 (sleeve), TFE-2X standard wall thickness (sleeve), P-440 (tape), Scotch 70 (tape), or CHR-A-2005 (tape).\n\n\t\t(3)\tIf damage or chafing is detected and adequate clearance exists, prior to further flight, repair the wire bundles in accordance with Boeing message, and accomplish either paragraph (a)(3)(i) or (a)(3)(ii) of this AD.\n\n\t\t\t(i)\tRepeat the visual inspection required by paragraph (a) of this AD, thereafter, each time the forward galley chiller is removed and reinstalled. Or\n\n\t\t\t(ii)\tPrior to further flight, install protective tape or sleeve over the wire bundles in accordance with Section 20-10-11 of the Boeing Standard Wiring Practices Manual. Operators shall use one of the following materials to protect the bundles: RT876 (sleeve), TFE-2X standard wall thickness (sleeve), P-440 (tape), Scotch 70 (tape), or CHR-A-2005 (tape).\n\n\t\t(4)\tIf damage or chafing is detected and inadequate clearance exists, prior to further flight, repair and modify the routing of the wire bundles in accordance with the Boeing message, and install protective tape or sleeve over the wire bundles in accordance with Section 20-10-11 of the Boeing Standard Wiring Practices Manual. Operators shall use one of the following materials to protect the bundles: RT876 (sleeve), TFE-2X standard wall thickness (sleeve), P-440 (tape), Scotch 70 (tape), or CHR-A-2005 (tape).\n\n\t(b)\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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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\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(c)\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(d)\tThe inspections and modification shall be done in accordance with Boeing Message Number M-7200-98-00140, dated January 11, 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(e)\tThis amendment becomes effective on April 21, 1998.

The FAA has received a report indicating that, soon after takeoff on a Boeing Model 767 series airplane, the engine indication and crew alerting system (EICAS) displayed several caution messages and several circuit breakers tripped. After landing, the cabin crew reported smoke coming from the forward galley air chiller, located below the forward galley door under the floor.\n\n\tThe smoke was produced by burning electrical wires. Investigation revealed that approximately 30 wires were damaged in bundles W272, W656, W782, and W254, forward of the P37 panel, adjacent to the AE0218 disconnect panel, and above the aft side of the forward galley air chiller. Further investigation revealed that the wire bundles do not have protective taping or sleeves and that adequate clearance does not exist between the wire bundles and the adjacent chiller. As a result, during the removal or reinstallation of the forward galley air chiller, the wire bundles may become damaged or chafed. When the insulation of the wire bundles is damaged or chafed, additional elements such as moisture, vibration, or conductive debris can result in arcing of the conductors.\n\n\tThese conditions, if not corrected, could result in burning of the damaged wires and the adjacent electrical wire bundles and consequent fire hazard for passengers and crewmembers, and failure of essential electrical systems.\n\nExplanation of Relevant Service Information\n\n\tThe FAA has reviewed and approved Boeing Message Number M-7200-98-00140, dated January 11, 1998, which describes procedures for a detailed visual inspection(s) for damage or chafing of the electrical wire bundles located in the right-hand outboard electronics equipment bay and for adequate clearance between the wire bundles and adjacent forward galley air chiller; and follow-on corrective actions. Boeing Message Number M-7200-98-00140, dated January 11, 1998, also references Boeing Standard Wiring Practices Manual (SWPM) D6-54446, as an additional source of service information.\n\nExplanation of the Requirement 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 arcing between exposed conductors, which could result in burning of the damaged wires and adjacent electrical bundles and consequent fire hazard for passengers and crewmembers, and failure of essential electrical systems. This AD requires accomplishment of the actions specified in the Boeing message described previously, except as discussed below.\n\nDifferences Between Rule and Service Bulletin\n\n\tWhile the Boeing Message Number M-7200-98-00140 does not describe procedures for repetitive inspections, this AD requires repetitive inspections for certain inspection results. For these certain inspection results, the FAA is not proposing to mandate the installation of protective tape or a sleeve over the wire bundles for several reasons:\n\n\t1. Accessing the wire bundles located forward of the P37 panel is easily accomplished.\n\n\t2. The subject damage or chafing is easily detectable by means of a detailed visual inspection.\n\n\t3. The failure of the wire bundles may adversely affect essential electrical systems; however, the detailed visual inspection will detect any damage or chafing of the wire bundles before they result in a hazardous condition.\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 concernedwith 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-95-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 itis 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\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.\n\nAdoption of the Amendment\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\t1. The authority citation for part 39 continues to read as follows:\nAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended)\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: