AD 94-07-07

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 and MD-11F airplanes, that requires modification of the fuel crossfeed low level dump system shutoff. This amendment is prompted by an FAA determination that, in the event of a failure of the number 2 bus tie relay and the subsequent loss of the number 2 electrical power source, an all-engine flameout event could occur due to fuel starvation during or shortly after a fuel dumping operation. The actions specified by this AD are intended to prevent loss of the fuel dump system shutoff due to a failure of the number 2 DC bus electrical relay and the subsequent loss of the number 2 electrical power source.

Final rule.

94-07-07 MCDONNELL DOUGLAS: Amendment 39-8865. Docket 93-NM-179-AD. \n\n\tApplicability: Model MD-11 and MD-11F airplanes having manufacturer's fuselage numbers 447 through 544 inclusive, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent loss of the fuel dump system shutoff due to a failure of the number 2 DC bus electrical relay and the subsequent loss of the number 2 electrical power source, accomplish the following: \n\n\t(a)\tWithin 24 months after the effective date of this AD, modify the fuel crossfeed low level dump system shutoff in accordance with McDonnell Douglas MD-11 Service Bulletin 28-48, dated September 30, 1993. Accomplishment of this modification constitutes terminating action for the revisions to the Airplane Flight Manual (AFM) required by paragraph (a) of AD 92-22-06, Amendment 39-8392. \n\n\t(b)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptablelevel 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: 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 Federal Aviation Regulations (FAR) 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 modification shall be done in accordance with McDonnell Douglas MD-11 Service Bulletin 28-48, dated September 30, 1993. 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, P.O. Box 1771, Long Beach, California 90801-1771, Attention: Business Unit Manager, Technical Administrative Support, Department L51, M.C. 2-98. 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, 3229 East Spring Street, Long Beach, 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 May 5, 1994.

A proposal to amend part 39 of the Federal Aviation Regulations to include an airworthiness directive (AD), that is applicable to certain McDonnell Douglas Model MD-11 and MD-11F airplanes, was published in the Federal Register on December 9, 1993 (58 FR 64708). That action proposed to require modification of the fuel crossfeed low level dump system shutoff.\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\n\tSeveral commenters support the proposed rule.\n\n\tOne commenter requests that the proposed compliance time of 15 months to modify the fuel crossfeed low level dump system shutoff be extended to 24 months to coincide with regularly scheduled "C" checks. The commenter states that a compliance time of 24 months would allow operators some latitude to schedule the accomplishment of this modification. The FAA concurs with the commenter's request to extend the compliance time for the modification requirement so that the modification can be performed at a maintenance base during regularly scheduled maintenance where special equipment and trained maintenance personnel will be available if necessary. Extending the compliance time by 9 additional months will not adversely affect safety since the interim procedures (via a revision to the Airplane Flight Manual (AFM)) required by AD 92-22-06, Amendment 39-8392 (57 FR 47570, October 19, 1992) will detect electrical malfunctions that may render the automatic fuel dump termination feature inoperative. Therefore, paragraph (a) of the final rule has been revised to specify a compliance time of 24 months.\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\n\tThere are approximately 98 McDonnell Douglas Model MD-11 and MD-11F airplanes of the affected design in the worldwide fleet. The FAA estimates that 43 airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per airplane to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will cost approximately $5,688 per airplane. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $258,774, or $6,018 per airplane.\n\n\tThe total 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\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 14 CFR part 39 of the Federal Aviation Regulations as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES\n\n\t1.\tThe authority citation for part 39 continues to read as follows:\n\nAuthority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.\n\n§ 39.13 - (Amended)\n\n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: