AD 2001-17-06

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 series airplanes, that requires replacement of the cargo roller circuit breakers with new circuit breakers, and reidentification of the aft circuit breaker panel; as applicable. This action is necessary to prevent possible overheating of cargo control unit components, which could result in smoke and/or fire in the cargo compartment. This action is intended to address the identified unsafe condition.

Final rule.

2001-17-06 McDonnell Douglas: Amendment 39-12397. Docket 2000-NM-186-AD. \n\n\tApplicability: Model MD-11 series airplanes, as listed in Boeing Alert Service Bulletin MD11-24A189, dated June 22, 2000; 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 possible overheating of cargo control unit (CCU) components, which could result in smoke and/or fire in the cargo compartment, accomplish the following: \n\nReplacement or Reidentification \n\n\t(a) Within 6 months after the effective date of this AD, do the applicable actions specified in paragraphs (a)(1) and (a)(2) of this AD per Boeing Alert Service Bulletin MD11-24A189, dated June 22, 2000. \n\n\t\t(1) For airplanes identified as Group 1 and Group 2 in the service bulletin: Replace the cargo roller circuit breakers with new circuit breakers. \n\n\t\t(2) For airplanes identified as Group 2 in the service bulletin: Reidentify the aft circuit breaker panel. \n\nAlternative Methods of Compliance \n\n\t(b) An 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. Operators shall submittheir 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\nSpecial Flight Permits \n\n\t(c) Special 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(d) The actions shall be done in accordance with Boeing Alert Service Bulletin MD11-24A189, dated June 22, 2000. 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, California90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). 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, 3960 Paramount Boulevard, Lakewood, California 90712; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(e) This amendment becomes effective on September 26, 2001.

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 20, 2001 (66 FR 10857). That action proposed to require replacement of the cargo roller circuit breakers with new circuit breakers, and reidentification of the aft circuit breaker panel; as applicable. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\nAddress Change for Obtaining Service Information \n\n\tThe airplane manufacturer states that the referenced department name, number, and mail code of the address for obtaining service information are incorrect in the proposed AD. The correct address is Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). The airplane manufacturer requests that the proposed AD be revised accordingly. The FAA agrees and has revised this address in the final rule. \n\nDelay Issuance of Final Rule \n\n\tOne commenter requests that the FAA delay issuance of the final rule until an on-aircraft verification has been performed. The FAA does not agree. To delay this final rule would be inappropriate, since we have determined that an unsafe condition exists and that an inspection must be conducted to ensure continued safety. \n\nReplace With Arc Fault Detection Circuit Breakers \n\n\tOne commenter states that the requirements of the proposed AD are acceptable, but questions the effectiveness of installing a smaller circuit breaker to protect a component. Based on lessons learned over the last two years related to the development of arc fault detection of circuit breakers, the commenter states that it seems unlikely that changing the size of the circuit breaker will be adequate in preventing further incidents of electrical failures in the cargo control unit (CCU) that have resulted in sparks or flame exiting the CCU. \n\n\tFrom these comments, the FAA infers that the commenter is requesting that the thermal circuit breakers be replaced with arc fault detection circuit breakers, rather than 5 amp thermal circuit breakers. The FAA does not agree. The FAA agrees that replacing 10 amp circuit breakers with 5 amp circuit breakers will not prevent all incidents of electrical failures in the CCU, which could result in sparks or flames. We also agree that arc fault detection of circuit breakers may provide additional protection to the existing thermal blankets. However, these circuit breakers are currently in the research and development phase. Industry has not published a set of performance requirements for such circuit breakers, and the FAA has not approved their installation. Although installation of these circuit breakers in the future may increase the effectiveness of circuit protection, the 5 amp thermal circuit breakers do protect the wiring against many types of electrical faults. Therefore, we have determined that replacing 10 amp circuit breakers with 5 amp thermal circuit breakers will further minimize the possibility of incidents of electrical failures in the CCU. No change to the final rule is necessary with regard to this point. \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 with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 104 Model MD-11 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 24 airplanes of U.S. registry will be affected bythis AD, that it will take approximately 2 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will be supplied by the airplane manufacturer at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $2,880, or $120 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted hereinwill not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132. \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\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\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: