AD 96-07-15

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes, that currently requires an inspection to detect chafing of or damage to the wire bundle in the overhead switch panel of the cockpit, application of spiral wrap to the wire bundle, and corrective actions, if necessary. That AD was prompted by reports of chafed and shorted wires that resulted in smoke emanating from the overhead switch panel of the cockpit. This amendment expands the applicability of the rule to include certain Model DC-9 and MD-90-30 series airplanes, and C-9 (military) series airplanes. This amendment also adds a requirement to reroute the wire bundle to preclude chafing and damage. The actions specified by this AD are intended to prevent the potential for fire and uncontrolled smoke throughout the cockpit as a result of chafing and shorting in the electrical wire bundles.

Final rule.

96-07-15 MCDONNELL DOUGLAS: Amendment 39-9565. Docket 95-NM-131-AD. Supersedes AD 95-09-10, Amendment 39-9213. \n\n\tApplicability: Model DC-9 and DC-9-80 series airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes, as listed in McDonnell Douglas DC-9 Alert Service Bulletin DC9- 24A157, dated April 11, 1995; and Model MD-90-30 series airplanes, as listed in McDonnell Douglas Alert Service Bulletin MD90-24A001, dated April 11, 1995; 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 otherwise 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 (d) 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 the potential for fire and uncontrolled smoke throughout the cockpit due to damaged electrical wiring, accomplish the following: \n\n\t(a)\tFor Model DC-9-80 series airplanes and Model MD-88 airplanes: Within 90 days after May 19, 1995 (the effective date of AD 95-09-10, amendment 39-9213), perform a visual inspection to detect chafing of or damage to the wire bundle in the overhead switch panel of the cockpit, in accordance with McDonnell Douglas Alert Service Bulletin DC9-24A157, dated April 11, 1995, or Revision 1, dated November 11, 1995. \n\n\t\t(1)\tIf no chafing or damage is detected, prior to further flight, apply spiral wrap to the wire bundle in accordance with the alert service bulletin. \n\n\t\t(2)\tIf the wire insulation is chafed, prior to further flight, repair it and then apply spiral wrap to the wire bundle in accordance with the alert service bulletin. \n\n\t\t(3)\tIf the wire conductor is damaged, prior to further flight, splice the wires and then apply spiral wrap to the wire bundle, in accordance with the alert service bulletin. \n\n\t(b)\tFor Model DC-9, C-9 (military), and MD-90-30 series airplanes: Within 6 months after the effective date of this AD, perform a visual inspection to detect chafing of or damage to the wire bundle in the overhead switch panel of the cockpit, in accordance with McDonnell Douglas Alert Service Bulletin DC9-24A157, dated April 11, 1995, or Revision 1 dated November 9, 1995 (for Model DC-9 and C-9 (military) series airplanes); or McDonnell Douglas Alert Service Bulletin MD90-24A001, dated April 11, 1995 (for Model MD-90-30 series airplanes); as applicable. \n\n\t\t(1)\tIf no chafing or damage is detected, prior to further flight, reroute the wire bundle in the overhead switch panel of the cockpit in accordance with either McDonnell Douglas Service Bulletin DC9-24-157, dated November 9, 1995 (for Model DC-9 series airplanes and C-9 (military) series airplanes), or McDonnell Douglas Service Bulletin MD90-24-001, dated November 9, 1995 (for Model MD-90-30 series airplanes), as applicable; or in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\t\t(2)\tIf the wire insulation is chafed, prior to further flight, repair it in accordance with the applicable alert service bulletin; then reroute the wire bundle in the overhead switch panel of the cockpit in accordance with either McDonnell Douglas Service Bulletin DC9-24-157, dated November 9, 1995 (for Model DC-9 series airplanes and C-9 (military) series airplanes), or McDonnell Douglas Service Bulletin MD90-24-001, dated November 9, 1995 (for Model MD-90-30 series airplanes), as applicable; or in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t\t(3)\tIf the wire conductor is damaged, prior to further flight, splice the wires in accordance with the applicable alert service bulletin; then reroute the wire bundle in the overhead switch panel of the cockpit in accordance with either McDonnell Douglas Service Bulletin DC9-24- 157, dated November 9, 1995 (for Model DC-9 series airplanes and C-9 (military) series airplanes), or McDonnell Douglas Service Bulletin MD90-24-001, dated November 9, 1995 (for Model MD-90- 30 series airplanes), as applicable; or in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(c)\tFor Model DC-9-80 series airplanes and Model MD-88 airplanes: Within 6 months after the effective date of this AD, reroute the wire bundle in the overhead switch panel of the cockpit in accordance with either McDonnell Douglas Service Bulletin DC9-24-157, dated November 9, 1995 (for Model DC-9 series airplanes and C-9 (military) series airplanes), or McDonnell Douglas Service Bulletin MD90-24-001, dated November 9, 1995 (for Model MD-90-30 series airplanes), as applicable; or in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(d)\t(1)\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. 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\t(2)\tAlternative methods of compliance approved in accordance with AD 95-09-10, amendment 39-9213, are approved as alternative methods of compliance with this AD. \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 the following McDonnell Douglas documents: \n\n\nService Bulletin \nNumber\nRevision Level\n Date\nAlert Service Bulletin MD90-24A001\n\n(original)\nApril 11, 1995\nService Bulletin \nMD90-24-001\n\n(original)\nNovember 9, 1995 \n\nAlert Service Bulletin DC9-24A157\n\n(original)\nApril 11, 1995 \nAlert Service Bulletin DC9-24A157\n\nRevision 1\nNovember 9, 1995 \nService Bulletin\n DC9-24-157\n(original)\nNovember 9, 1995\n\nThe incorporation by reference of McDonnell Douglas Alert Service Bulletin DC9-24A157, dated April 11, 1995, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of May 19, 1995 (60 FR 21977, May 4, 1995). The incorporation by reference of the remainder of the service documents listed above is 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, 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(g)\tThis amendment becomes effective on May 15, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 95-09-10, amendment 39-9213 (60 FR 21977, May 4, 1995), which currently is applicable to certain McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes, was published in the Federal Register on September 15, 1995 (60 FR 47901). The action proposed to supersede AD 95-09-10 to continue to require a one- time visual inspection to detect chafing of or damage to the wire bundle in the overhead switch panel of the cockpit, application of spiral wrap to the wire bundle, repair of chafed wire insulation, splicing of damaged wires, and rerouting the wire bundle. The action also proposed to expand the applicability of the rule to include certain Model DC-9 and MD-90-30 series airplanes, and C-9 (military) series airplanes. This amendment also adds a requirement to reroute the wire bundle to preclude chafing and damage. \n\n\tInterested persons havebeen afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\n\tOne commenter supports the proposed rule. \n\n\tTwo commenters request that Model DC-9 series airplanes be excluded from the applicability of the proposal. One of these commenters states that the FAA has not proven that the potential for chafing of wire bundles exists for Model DC-9 series airplanes. The other commenter states that it has inspected 35 in-service airplanes in its fleet and has found only one chafed wire bundle, and has never, in 25 years of service, found any damaged wire bundles. \n\n\tThe FAA does not concur. Although there have been no reported cases of damage to the wire bundle on any in-service Model DC-9 series airplane, the FAA has received reports of chafing found on the wire bundle on in-service Model DC-9 series airplanes. Therefore, the potential for damage still exists when the wire bundle is improperly routed in theoverhead switch panel of the cockpit such that chafing occurs. The FAA has determined that rerouting the wire bundle will prevent the potential for chafing and thereby prevent the potential for a consequent fire and uncontrolled smoke throughout the cockpit. \n\n\tTwo commenters request a revision to paragraph (b) of the proposal to delete the requirement to apply spiral wrap to the wire bundle following findings of chafing or damage to the wire bundle on Model DC-9, MD-90-30, and C-9 (military) series airplanes. The commenters state that these airplanes should not be required to apply spiral wrap, since the proposal also requires rerouting of the wire bundles following application of spiral wrap. \n\n\tThe FAA concurs. Since issuance of the NPRM, the FAA has reviewed and approved McDonnell Douglas Service Bulletins DC9-24-157 and MD90-24-001, both dated November 9, 1995, which describe procedures for rerouting the electrical wiring in the overhead switch panel to clear the cabin temperature indicator housing. As explained in the preamble to AD 95-09-10, the FAA considers the application of spiral wrap to be only a temporary measure to protect against chafing of the wire bundle. The FAA's intent was to require, in AD 95-09-10, application of spiral wrap only for Model DC-9-80 series airplanes and Model MD-88 airplanes, since the procedures to reroute the wire bundles for these airplanes had not yet been developed at the time AD 95-09-10 was issued. Since procedures for rerouting the wire bundles have now been developed for all airplanes, the FAA finds that operators must reroute the wire bundles immediately following findings of chafed or damaged wire bundles on Model DC-9, MD-90-30, and C-9 (military) series airplanes. The FAA has determined that applying the spiral wrapping for these airplanes would not necessarily enhance safety, and would cause operators to incur an unnecessary expense. Consequently, paragraph (b) of the final rule has been revised to remove the requirement to spiral wrap the wire bundle prior to rerouting the wire bundle. Additionally, paragraph (b) of the final rule has been revised to reference McDonnell Douglas Service Bulletins DC9-24-157 and MD90- 24-001 as additional sources of service information to accomplish rerouting of the wire bundle. \n\n\tAdditionally, the FAA has revised paragraph (c) of the final rule to include an applicability statement that limits the requirement of that paragraph (rerouting the wire bundles within 6 months after the effective date of the AD) to only Model DC-9-80 series airplanes and Model MD-88 airplanes. (The requirement to reroute the wire bundle for all other airplanes is required immediately following the inspection required by paragraph (b) of the final rule.) \n\n\tTwo commenters request that previously approved alternative methods of compliance (AMOC) with AD 95-09-10 continue to be acceptable for the requirements of the proposal. The commenters state that such a provisionin the proposal would preclude operators from having to obtain approval of additional AMOC's unnecessarily. The FAA concurs. NOTE 3 from the proposal has been changed from a note to paragraph (d)(2) of the final rule to emphasize that operators need not apply for approval of an additional AMOC if the FAA had previously approved an AMOC to AD 95-09-10. \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\n\tThere are approximately 2,012 Model DC-9, DC-9-80, and MD-90-30 series airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes of the affected design in the worldwide fleet. The FAA estimates that 816 airplanes of U.S. registry will be affected by this AD. \n\n\tThe requirement to inspect and spiral wrap the wire bundle, which was previously required by AD 95-09-10, continues to be applicable to 614 Model DC-9-80 series airplanes and Model MD- 88 airplanes of U.S. registry. This action takes approximately 3 work hours per airplane to accomplish, at an average labor rate is of $60 per work hour. Required parts cost approximately $5 per airplane. Based on these figures, the cost impact of the current requirements of that AD on U.S. operators of the affected airplanes is estimated to be $113,950, or $185 per airplane. However, in consideration of the compliance time and effective date of AD 95-09-10, the FAA assumes that U.S. operators of airplanes that are subject to the requirements of that AD have already initiated the required actions. Therefore, the requirement to inspect and spiral wrap the wire bundle likely adds no new costs associated with those airplanes. \n\n\tThe requirements of this new AD action to inspect and spiral wrap the wire bundleare also applicable to approximately 202 Model DC-9, MD-9-30, and C-9 (military) series airplanes of U.S. registry. Based on the figures discussed above, the new costs imposed by this AD on U.S. operators of these airplanes are estimated to be $37,370, or $185 per airplane. \n\n\tThe requirement to reroute the wire bundle that is required by this new AD is applicable to all 816 airplanes of U.S. registry. Accomplishing this rerouting will take approximately 0.5 work hour per airplane, at an average labor rate of $60 per work hour. Required parts will cost approximately $5 per airplane. Based on these figures, the cost impact on U.S. operators of the new requirements of this AD is estimated to be $28,560, or $35 per airplane. \n\n\tThe cost impact figures discussed above, associated with the new requirements of this AD, are based on assumptions that no operator has yet accomplished any of those requirements, and that no operator would accomplish those actions in the future if this ADwere not adopted. \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\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 USC 106(g), 40113, 44701. \n\n§ 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by removing amendment 39-9213 (60 FR 21977, May 4, 1995), and by adding a new airworthiness directive (AD), amendment 39-9565, to read as follows: