AD 95-22-13

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This action requires an inspection to determine proper clamping and to detect damage of a wire bundle in the avionics compartment, and repair, if necessary. This amendment is prompted by a report of smoke and fire in the avionics compartment floor area that was caused by electrical arcing that occurred as the result of chafed wiring. The actions specified in this AD are intended to prevent smoke and fire in the avionics compartment due to such electrical arcing in the wire bundle; that condition could pose a hazard to the continued safe flight of the airplane.

Final rule; request for comments.

95-22-13 MCDONNELL DOUGLAS: Amendment 39-9421. Docket 95-NM-205-AD. \n\n\tApplicability: Model MD-11 series airplanes having manufacturer's fuselage numbers 0447 through 0527, inclusive, 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 use the authority provided in paragraph (c) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent smoke and fire in the avionics compartment due to electrical arcing that results from chafing damage to wires, accomplish the following: \n\n\t(a)\tWithin 30 days after the effective date of this AD, perform a visual inspection of the wire bundle in the avionics compartment for improper clamping and/or damage of the wiring, in accordance with McDonnell Douglas Alert Service Bulletin MD11-24A094, dated October 12, 1995. \n\n\t\t(1)\tIf the wire bundle is properly clamped and no damage is detected, no further action is required by this AD. \n\n\t\t(2)\tIf the wire bundle is improperly clamped, prior to further flight, reposition the wire in the clamp in accordance with the alert service bulletin. \n\n\t\t(3)\tIf any wiring is damaged, prior to further flight, accomplish either paragraph (a)(3)(i), or (a)(3)(ii) of this AD, as applicable: \n\n\t\t\t(i)\tFor wires (Loop A and B) having damage to any one fire detector controller (engines 1, 2, 3, and APU): Prior to further flight, splice one loop and replace the wire for the other loop in accordance with the alert service bulletin. \n\n\t\t\t(ii)\tFor wiring having damage other than that identified in paragraph (a)(3)(i) of this AD: Prior to further flight, repair the wiring in accordance with the alert service bulletin. \n\n\t(b)\tWithin 15 days after accomplishing the visual inspection required by paragraph (a) of this AD, submit a report of the inspection results (both positive and negative findings) to the Manager, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712; telephone (310) 627-5200; fax (310) 627-5210. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of thePaperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. \n\n\t(c)\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, Los Angeles 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, Los Angeles ACO. \n\n\tNOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\n\t(d)\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(e)\tThe actions shall be done in accordance with McDonnell Douglas Alert Service Bulletin MD11-24A094, dated October 12, 1995. 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 McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Department C1-L51 (2-60). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(f)\tThis amendment becomes effective on November 20, 1995.

Recently, an operator of a McDonnell Douglas Model MD-11 series airplane reported that chafing and subsequent electrical arcing of wires in the avionics compartment floor area caused damage to wiring, insulation blankets, and equipment rack structure. The arcing also caused fire and smoke in the avionics compartment. Investigation revealed that the wire bundle was outside of the wire clamp, which was the result of improper clamping during manufacturing. This condition allowed the wiring to chafe against the clamp hardware and equipment rack structure. Chafing and subsequent electrical arcing of the wire bundle, if not corrected, could result in fire and smoke in the avionics compartment area. This condition could pose a hazard to the continued safe flight of the airplane. \n\n\tThe FAA has reviewed and approved McDonnell Douglas Alert Service Bulletin MD11- 24A094, dated October 12, 1995, which describes procedures for a visual inspection of the wire bundle in the avionics compartment for improper clamping or damage to the wiring. The service bulletin also contains procedures for repositioning of improperly clamped wire assemblies; and either splicing and replacing, or repairing damaged wiring. The alert service bulletin recommends that these actions be accomplished within six months. \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other McDonnell Douglas MD-11 series airplanes of the same type design, this AD is being issued to prevent fire and/or smoke due to chafing and arcing of the wire bundle in the avionics compartment area. This AD requires a one-time visual inspection of the wire bundle in the avionics compartment to determine proper clamping of the wire bundle and to detect any damage of the wiring. Improperly clamped wire bundles must be properly repositioned. Damaged wiring must be repaired. The actions are required to be accomplished in accordance with the alert service bulletin described previously. \n\n\tOperators should note that, although the alert service bulletin recommends accomplishing the visual inspection within six months (after the release of the service bulletin), the FAA has determined that an interval of six months would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the inspection (less than one hour). In light of all of these factors, the FAA finds 30 days to be an appropriate compliance time for initiating the required actions in that it represents the maximum interval of time allowable for affected airplanes to continue to operate without compromising safety. \n\n\tThis AD also requires that operators report positive and negative results ofthe inspection to the FAA. \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 95-NM-205-AD." The postcard will be date stamped and returned to the commenter. \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\n Adoption 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\nAuthority: 49 USC 106(g), 40101, 40113, 44701. \n\n§ 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: