AD 2004-07-12

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 airplanes. For some airplanes, this action requires replacing one 3-phase limiter block assembly, 6 current limiters, and hardware for 9 electrical cables with new parts. For other airplanes, this action requires inspecting 6 current limiters and 3 spare current limiters and replacing any defective current limiters with new current limiters. This action is necessary to prevent overheating of the terminal studs on the 3-phase limiter blocks and associated current limiters, which could cause a fire in the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2004-07-12 McDonnell Douglas: Amendment 39-13556. Docket 2001-NM- 226-AD. \n\n\tApplicability: Model MD-90-30 airplanes, as listed in McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001, or McDonnell Douglas Alert Service Bulletin MD90- 24A043, Revision 01, dated March 12, 2001; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent overheating of the terminal studs on the 3-phase limiter blocks and associated current limiters, which could cause a fire in the airplane, accomplish the following: \n\nInspection and Replacement \n\n\t(a) For those airplanes listed as Group 1 airplanes in McDonnell Douglas Alert Service Bulletin MD90-24A043, Revision 01, dated March 12, 2001, which are also listed in McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001: Within 6 months after the effective date of this AD, accomplish the following actions: \n\n\t(1) Inspect the 3 spare current limiters located in the electrical power center (EPC) in accordance with the Accomplishment Instructions of McDonnell Douglas Alert Service Bulletin MD90- 24A043, Revision 01, dated March 12, 2001. If the inspection reveals that any of the current limiters located in the electrical power unit are defective, before further flight replace the defective current limiter(s) with new current limiter(s) in accordance with the alert service bulletin. \n\n\t(2) Prior to or concurrent with accomplishment of paragraph (a)(1) of this AD, accomplish the following actions in accordance with McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001: \n\n\t(i) Replace the 3-phase limiter block assembly and associated clear cover of the EPC with a serialized 3-phase limiter block assembly and a new clear cover. \n\n\t(ii) Replace the 6 current limiters and attaching parts on the limiter block with new current limiters and attaching parts. \n\n\t(iii)Replace hardware for 9 electrical cables attached to the limiter block with new attaching hardware. \n\nReplacement \n\n\t(b) For those airplanes listed in McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001: Within 6 months after the effective date of this AD, accomplish the following actions in accordance with the Accomplishment Instructions of the alert service bulletin: \n\n\t(1) Replace the 3-phase limiter block assembly and associated clear cover of the EPC with a serialized 3-phase limiter block assembly and a new clear cover. \n\n\t(2) Replace the 6 current limiters and attaching parts on the limiter block with new current limiters and attaching parts. \n\n\t(3) Replace hardware for 9 electrical cables attached to the limiter block with new attaching hardware. \n\nOther Inspection \n\n\t(c) For those airplanes listed as Group 2 airplanes in McDonnell Douglas Alert Service Bulletin MD90-24A043, Revision 01, dated March 12, 2001: Within 6 monthsafter the effective date of this AD, accomplish the following actions in accordance with the Accomplishment Instructions of the alert service bulletin.\n \n\t(1) Inspect the 6 current limiters and attaching hardware on the 3-phase limiter blocks and the 3 spare current limiters located in the EPC to determine whether any of the current limiters are defective.\n \n\t(2) If the inspection required by paragraph (c)(1) of this AD reveals that any of the current limiters are defective, before further flight replace the defective current limiters with new current limiters, in accordance with Figure 1 of the Accomplishment Instructions. \n\nParts Installation \n\n\t(d) As of the effective date of this AD, no person shall install on any airplane a Tri-Star 3-phase limiter block assembly having part number (P/N) C-1301-3 or a Burndy 3-phase limiter block assembly having P/N F6H-2, unless that 3-phase limiter block assembly has serial number 3015 or higher. \n\nInformation Submission \n\n\t(e) Although McDonnell Douglas Alert Service Bulletin MD90- 24A031, Revision 01, dated February 28, 2001, referenced in this AD specifies that certain information is to be submitted to the airplane manufacturer, this AD does not include such a requirement. \n\nAlternative Methods of Compliance \n\n\t(f) In accordance with 14 CFR 39.19, the Manager, Los Angeles Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD. \n\nIncorporation by Reference \n\n\t(g) The actions shall be done in accordance with McDonnell Douglas Alert Service Bulletin MD90-24A043, Revision 01, dated March 12, 2001; and McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001; as applicable. 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 Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(h) This amendment becomes effective on May 11, 2004.

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-90-30 airplanes was published in the Federal Register on January 7, 2004 (69 FR 900). For some airplanes, that action proposed to require replacing one 3-phase limiter block assembly, 6 current limiters, and hardware for 9 electrical cables with new parts. For other airplanes, that action proposed to require inspecting 6 current limiters and 3 spare current limiters and replacing any defective current limiters with new current limiters. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. \n\nExplanation of Change to Paragraph (e) of the Proposed AD \n\n\tParagraph (e) of proposed AD states, "Although the service bulletin referenced in this AD specifies that certain information is to be submitted to the FAA, this AD does not include such requirements." The proposed AD references two service bulletins as the appropriate sources for accomplishing the required actions. Our intent was to refer specificially to McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001, in paragraph (e). Also, that service bulletin does not specify to submit certain information to the FAA, but rather to the airplane manufacturer "for FAA accountability purposes." Therefore, we have revised paragraph (e) of the final rule to clarify these points. \n\nConclusion \n\n\tThe 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 29 airplanes in the worldwide fleet which are listed in McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001. The FAA estimates that 18 airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the actions required in paragraph (b) of this AD, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the actions required in paragraph (b) of this AD on U.S. operators is estimated to be $5,655, or $195 per airplane. \n\n\tThere are approximately 4 airplanes in the worldwide fleet which are listed in McDonnell Douglas Alert Service Bulletin MD90-24A031, Revision 01, dated February 28, 2001, and are also listed as Group 1 airplanes in McDonnell Douglas Alert Service Bulletin MD90-24A043, Revision 01, dated March 12, 2001. None of those airplanes are on the U.S. registry. \n\n\tThere are approximately 5 airplanes in the worldwide fleet which are listed as Group 2 airplanes in McDonnell Douglas Alert Service Bulletin MD90-24A043, Revision 01, dated March 12, 2001. The FAA estimates that 1 airplane of U.S. registrywill be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the actions required in paragraph (c) of this AD, and that the average labor rate is $65 per work hour. The manufacturer may cover the cost of replacement parts associated with this AD, subject to warranty conditions. Based on these figures, the cost impact of the actions required in paragraph (c) of this AD on U.S. operators is estimated to be $195.\n \n\tThe cost impact figures discussed above are 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 herein will 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 thelocation 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. \nAdoption of the Amendment \n\nAccordingly, 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\n1. 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\n2. Section 39.13 is amended by adding the following new airworthiness directive: