AD 99-09-03

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This action requires a one-time inspection of the wiring and wire bundles of the aft main avionics rack (MAR) to determine if the wires are damaged, or riding or chafing on structure, clamps, braces, standoffs, or clips, and to detect damaged or out of alignment rubber cushions inserts of the wiring clamps; and corrective actions, if necessary. This amendment is prompted by an incident in which the automatic and manual cargo door test in the cockpit was inoperative during dispatch of the airplane, due to the wiring of the MAR chafing against clamps as a result of the wire bundles being installed improperly during production of the airplane. The actions specified in this AD are intended to ensure that the wires that route from the main wire bundles to the MAR and associated brackets, clamps, braces, standoffs, and clips are installed properly. Improper installation of such wiring and structure could cause chafing of the wire/wire bundles, which could result in electrical arcing, smoke, and possible fire in the MAR.

Final rule; request for comments.

99-09-03 MCDONNELL DOUGLAS: Amendment 39-11135. Docket 99-NM-44-AD. \n\n\tApplicability: Model MD-11 series airplanes, manufacturer's fuselage numbers 0447 through 0464 inclusive, 466 through 0552 inclusive, 0554 through 0596 inclusive, and 0597 through 0628 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 request approval for an alternative method of compliance in accordance with paragraph (g) 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 ensure that the wires that route from the main wire bundles to the MAR and associated brackets, clamps, braces, standoffs, and clips are installed properly, accomplish the following: One-Time Inspection \n\n\t(a)\tWithin 60 days after the effective date of this AD, perform a one-time inspection of the wiring and wire bundles of the aft main avionics rack (MAR) to determine if the wires are damaged, or riding or chafing on structure, clamps, braces, standoffs, or clips, and to detect damaged or out of alignment rubber cushions inserts of the wiring clamps; in accordance with McDonnell Douglas Alert Service Bulletin MD11-24A146, dated February 1, 1999. \n\n\tNOTE 2: Where there are differences between this AD and the referenced alert service bulletin, the AD prevails. \nCorrective Actions \n\n\t(b)\tIf any damaged wiring is detected during the inspection required by paragraph (a) of this AD, prior to further flight, repair in accordance with the alert service bulletin. \n\n\t(c)\tIf any wire/wire bundle is detected to be riding or chafing on the subject areas during the inspection required by paragraph (a) of this AD, prior to further flight, accomplish paragraphs (c)(1), (c)(2), and (c)(3) of this AD. \n\n\tNOTE 3: Operators should note that paragraph 3.A.2. of the Accomplishment Instructions of McDonnell Douglas Alert Service Bulletin MD11-24A146, dated February 1, 1999, incorrectly states, ". . . as outlined in paragraph 3.B.2 . . ." The correct reference is paragraph 3.A.2. \n\n\t\t(1)\tRoute and tie all wires/wire bundles so that they are not in contact with adjacent wire bundles, clamps, or structure, and if necessary, install silicone rubber coated glass cloth wrapping on wiring; in accordance with the alert service bulletin. \n\n\t\t(2)\tPerform an inspection of all brackets, clamps, braces, standoffs, and clips to make sure they are not bent or twisted and do not come in contact with wires/wire bundles, in accordance with the alert service bulletin. If any of these parts is bent or twisted or is in contact with wires/wire bundles, prior to further flight, reposition in accordance with the alert service bulletin. \n\n\t\t(3)\tPerform an inspection of the clamps for proper alignment or for damage of the rubber cushion, in accordance with alert service bulletin. If any clamp is not aligned properly, prior to further flight, realign clamp in accordance with the alert service bulletin. If any rubber cushion is damaged, prior to further flight, replace the clamp with a new or serviceable clamp in accordance with Chapter 20-30-01 of McDonnell Douglas MD-11 Airplane Maintenance Manual (AMM), dated February 1, 1999. \n\n\t(d)\tIf any damaged rubber cushion insert is detected during the inspection required by paragraph (a) of this AD, prior to further flight, replace the clamp with a new or serviceable clamp in accordance with Chapter 20-30-01 of McDonnell Douglas MD-11 Airplane Maintenance Manual, dated February 1, 1999. \n\n\t(e)\tIf any rubber cushion insert is out of alignment, prior to further flight, visually realign the cushion. \n\nReporting Requirement \n\n\t(f)\tWithin 10 days after accomplishing the 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), FAA, Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood, California 90712-4137; fax (562) 627-5210. 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\nAlternative Methods of Compliance \n\n\t(g)\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 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, Los Angeles ACO. \n\n\tNOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\nSpecial Flight Permits \n\n\t(h)\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\nIncorporation by Reference \n\n\t(i)\tExcept as provided by paragraphs (c)(2), (c)(3), (d), and (e) of this AD, the actions shall be done in accordance with McDonnell Douglas Alert Service Bulletin MD11-24A146, dated February 1, 1999. 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 Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 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(j)\tThis amendment becomes effective on May 7, 1999.

As part of its practice of re-examining all aspects of the service experience of a particular aircraft whenever an accident occurs, the FAA has become aware of an incident in which the automatic and manual cargo door test in the cockpit was inoperative. This incident occurred on a McDonnell Douglas Model MD-11 series airplane during dispatch. \n\n\tInvestigation revealed the insulation of a wire located on the aft main avionics rack (MAR) was worn through, and that the wire shorted to a coax cable clamp. The wires that route from the main wire bundles to the MAR also were found contacting clamps at other locations of the MAR. The cause of such chafing has been attributed to improper installation of the wire bundles in the MAR during production of the airplane. (This incident is not considered to be related to an accident that occurred off the coast of Nova Scotia involving a McDonnell Douglas Model MD-11 series airplane. The cause of that accident is still under investigation.) \n\n\tImproper installation of the wires that route from the main wire bundles to the MAR or improper installation of associated brackets, clamps, braces, standoffs, or clips could cause chafing of the wire/wire bundles, which could result in electrical arcing, smoke, and possible fire in the MAR. \n\nOther Related Rulemaking \n\n\tThe FAA, in conjunction with Boeing and operators of Model MD-11 series airplanes, is continuing to review all aspects of the service history of those airplanes to identify potential unsafe conditions and to take appropriate corrective actions. This airworthiness directive (AD) is one of a series of actions identified during that process. The process is continuing and the FAA may consider additional rulemaking actions as further results of the review become available. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved McDonnell Douglas Alert Service Bulletin MD11-24A146, dated February 1, 1999. The alert service bulletin describes procedures for a one-time inspection of the wiring and wire bundles of the aft MAR to determine if the wires are damaged, or riding or chafing on structure, clamps, braces, standoffs, or clips, and to detect damaged or out of alignment rubber cushions inserts of the wiring clamps; and corrective actions, if necessary. The corrective actions include repairing damaged wiring; routing and tying all wires/wire bundles so that they are not in contact with adjacent wire bundles, clamps, or structure; installing silicone rubber coated glass cloth wrapping on wiring; and inspecting all brackets, clamps, braces, standoffs, and clips to make sure they are not bent or twisted and come in contact with wires/wire bundles. Accomplishment of the actions specified in the alert service bulletin is intended to adequately address the identified unsafe condition. \n\nExplanation of the Requirements of the Rule \n\n\tSince an unsafe condition has been identified that islikely to exist or develop on other McDonnell Douglas Model MD-11 series airplanes of the same type design, this AD is being issued to ensure that the wires that route from the main wire bundles to the MAR and associated brackets, clamps, braces, standoffs, and clips are installed properly. Improper installation of such wiring and structure could cause chafing of the wire/wire bundles, which could result in electrical arcing, smoke, and possible fire in the MAR. This AD requires accomplishment of the actions specified in the alert service bulletin described previously, except as discussed below. This AD also requires that operators submit a report of the inspection results to the FAA. \n\nDifferences Between the AD and the Referenced Alert Service Bulletin \n\n\tThe alert service bulletin specifies the following corrective actions for certain conditions: realigning rubber cushion and replacing clamp. However, the alert service bulletin does not provide any instructions for accomplishment of those procedures or reference other service information. The FAA has verified with the manufacturer that the appropriate source of service information for accomplishment of those procedures is Chapter 20-30-01 of McDonnell Douglas MD-11 Airplane Maintenance Manual (AMM), dated February 1, 1999. Therefore, this AD requires that those actions be accomplished in accordance with the AMM. \n\n\tOperators should note that, although the alert service bulletin recommends accomplishing the one-time inspection within 6 months (after the release of the service bulletin), the FAA has determined that an interval of 6 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(two work hours). In light of all of these factors, the FAA finds a 60-day compliance time for initiating the required actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety. \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 RulesDocket 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 submittedin response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 99-NM-44-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\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: \n\nAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding thefollowing new airworthiness directive: