AD 97-10-12

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 series airplanes, that requires a one-time inspection to detect riding, chafing, or damage of the wire bundles adjacent to the disconnect panel bracket of the observer's station. This amendment also requires repair or replacement of damaged wires with new or serviceable wires; installation of anti-chafing sleeving on the wire bundles, if necessary; and installation of grommet along the entire upper aft edge of the disconnect panel bracket. This amendment is prompted by a report indicating that the circuit breakers tripped on a Model MD-11 series airplane due to inflight arcing behind the avionics circuit breaker panel as a result of chafing of the wire bundles adjacent to the disconnect panel bracket assembly. The actions specified by this AD are intended to detect and correct such chafing, which could result in a fire in the wire bundles and smoke in the cockpit.

Final rule.

97-10-12 MCDONNELL DOUGLAS: Amendment 39-10024. Docket 96-NM-283-AD. \n\n\tApplicability: Model MD-11 series airplanes, as listed in McDonnell Douglas Service Bulletin MD11-24-111, dated December 3, 1996; 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 detect and correct chafing of the wire bundles adjacent to the disconnect panel bracket assembly and consequent inflight arcing behind the avionics circuit breaker, which could result in a fire in the wire bundles and smoke in the cockpit, accomplish the following: \n\n\t(a)\tWithin 6 months after the effective date of this AD: Perform a one-time inspection to detect riding, chafing, or damage of the wire bundles adjacent to the disconnect panel bracket of the observer's station, in accordance with McDonnell Douglas Service Bulletin MD11-24-111, dated December 3, 1996. \n\n\t\t(1)\tCondition 1. If any riding or chafing is found, and if any damage is found: Prior to further flight, repair or replace any damaged wires with new or serviceable wires; install anti-chafing sleeving on the wire bundles; and install a grommet along the entire upper aft edge of the disconnect panel bracket; in accordance with the service bulletin.(2)\tCondition 2. If any riding or chafing is found, but no damage is found: Prior to further flight, install anti-chafing sleeving on the wire bundles, and install a grommet along the entire upper aft edge of the disconnect panel bracket, in accordance with the service bulletin. \n\n\t\t(3)\tCondition 3. If no riding, chafing, or damage is found: Prior to further flight, install a protective grommet along the entire upper aft edge of the disconnect panel bracket in accordance with the service bulletin. \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, 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 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(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 actions shall be done in accordance with McDonnell Douglas Service Bulletin MD11-24-111, dated December 3, 1996. 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, Transport Airplane Directorate, Los Angeles Aircraft CertificationOffice, 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(e)\tThis amendment becomes effective on June 16, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes was published in the Federal Register on February 18, 1997 (62 FR 7182). That action proposed to require a one-time inspection to detect riding, chafing, or damage of the wire bundles adjacent to the disconnect panel bracket of the observer's station. That action also proposed to require repair or replacement of damaged wires with new or serviceable wires; installation of anti-chafing sleeving on the wire bundles, if necessary; and installation of grommet along the entire upper aft edge of the disconnect panel bracket. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the two comments received. \n\n\tBoth commenters support the proposal. \n\nConclusion \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 as proposed. \n\nCost Impact \n\n\tThere are approximately 86 McDonnell Douglas Model MD-11 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 45 airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $8,100, or $180 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. \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\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: Authority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: