AD 95-06-04

This amendment adopts a new airworthiness directive (AD), applicable to McDonnell Douglas Model DC-9-80 series airplanes, that requires inspection and replacement of certain suspect horizontal stabilizer primary trim motors. This amendment is prompted by an analysis which revealed that certain incorrectly manufactured motor shafts could fail prematurely and, in turn, cause the primary trim motor to fail. The actions specified by this AD are intended to prevent such failures of the primary trim motor, which could ultimately result in reduced controllability of the airplane.

Final rule.

95-06-04 McDONNELL DOUGLAS: Amendment 39-9174. Docket 94-NM-149-AD.\n\n\tApplicability: Model DC-9-80 series airplanes; as listed in McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994; 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 use the authority provided in paragraph (b) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.\n\n\tCompliance: Required as indicated, unless accomplished previously.\n\n\tTo prevent failure of the horizontal stabilizer primary trim motor, accomplish the following:\n\n\t(a)\tWithin 6 months after the effective date of this AD, conduct a visual inspection of the horizontal stabilizer primary trim motor to determine if the motor is identified with one of the suspect serial numbers listed in McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994. Conduct this inspection in accordance with the procedures specified in that service bulletin.\n\n\t\t(1)\tIf the horizontal stabilizer primary trim motor is not identified with a suspect serial number, no further action is required by this AD.\n\n\t\t(2)\tIf the horizontal stabilizer primary trim motor is identified with a suspect serial number, prior to further flight, replace themotor 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 inspection and replacement shall be done in accordance with McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994. 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, Dept. L51, M.C. 2-98. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at FAA, Los Angeles Aircraft Certification Office, Transport Airplane Directorate, 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 April 21, 1995.

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 McDonnell Douglas Model DC-9-80 series airplanes was published in the Federal Register on October 18, 1994 (59 FR 52482). That action proposed to require inspecting the horizontal stabilizer primary trim motor to determine if the motor is one having a suspect serial number, and replacing the suspect motors.\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 rule.\n\n\tAs a result of recent communications with the Air Transport Association (ATA) of America, the FAA has learned that, in general, some operators may misunderstand the legal effect of AD's on airplanes that are identified in the applicability provision of the AD, but that have been altered or repaired in the area addressed by the AD. The FAA points out that all airplanes identified in the applicability provision of an AD are legally subject to the AD. If an airplane has been altered or repaired in the affected area in such a way as to affect compliance with the AD, the owner or operator is required to obtain FAA approval for an alternative method of compliance with the AD, in accordance with the paragraph of each AD that provides for such approvals. A note has been added to this final rule to clarify this requirement.\n\n\tThe FAA has recently reviewed the figures it has used over the past several years in calculating the economic impact of AD activity. In order to account for various inflationary costs in the airline industry, the FAA has determined that it is necessary to increase the labor rate used in these calculations from $55 per work hour to $60 per work hour. The economic impact information, below, has been revised to reflect this increase in the specified hourly labor rate.After 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 26 Model DC-9-80 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 13 airplanes of U.S. registry will be affected by this AD, that it will take approximately .5 work hour per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $390, or $30 per airplane.\n\n\tReplacement of suspect motors will require 4.5 work hours to accomplish, at an average labor charge of $60 per work hour. Required replacement parts will be provided by SundstrandElectric Power Systems (the manufacturer of the horizontal stabilizer primary trim motors) at no charge to operators. Based on these figures, the total cost impact is estimated to be $3,510, or $270 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\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.\n\nAdoption of the Amendment\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\t1.\tThe authority citation for part 39 continues to read as follows:\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\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: