AD 96-05-01

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-80 series airplanes, that currently requires inspection and replacement of certain suspect horizontal stabilizer primary trim motors. That AD was 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 in that AD are intended to prevent such failures of the primary trim motor, which could ultimately result in reduced controllability of the airplane. This amendment expands the applicability of the existing AD to include additional affected airplanes.

Final rule.

96-05-01 McDONNELL DOUGLAS: Amendment 39-9525. Docket 95-NM-118-AD. Supersedes AD 95-06-04, Amendment 39-9174. \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, and in McDonnell Douglas MD-80 Alert Service Bulletin A27-342, Revision 1, dated May 15, 1995; 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 otherwise 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 (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressedby 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\tNOTE 2: Paragraph (a) of this AD merely restates the requirements of paragraph (a) of AD 95-06-04, amendment 39-9174. As allowed by the phrase, "unless accomplished previously," if those requirements of AD 95-06-04 have already been accomplished, this AD does not require that those actions be repeated. \n\n\tTo prevent failure of the horizontal stabilizer primary trim motor, accomplish the following: \n\n\t(a)\tFor airplanes listed in McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994: Within 6 months after April 21, 1995 (the effective date of AD 95-06-04, amendment 39-9174), conduct either a visual inspection of the horizontal stabilizer primary trim motor or a records search 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, or Revision 1, dated May 15, 1995. If a visual inspection is conducted, it must be performed in accordance with the procedures specified in the service bulletin. \n\n\t\t(1)\tIf the horizontal stabilizer primary trim motor is not identified with a suspect serial number; or if the horizontal stabilizer primary trim motor has been modified previously in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; 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 and has not been modified previously in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; prior to further flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii) of this AD. \n\n\t\t\t(i)\tReplace the motor in accordance with the McDonnell Douglas alert service bulletin. Or \n\n\t\t\t(ii)\tModify the motor in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; and install the modified motor in accordance with the McDonnell Douglas alert service bulletin. \n\n\t(b)\tFor airplanes listed in McDonnell Douglas MD-80 Alert Service Bulletin A27-342, Revision 1, dated May 15, 1995, and not subject to paragraph (a) of this AD: Within 6 months after the effective date of this AD, conduct either a visual inspection of the horizontal stabilizer primary trim motor or a records search 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, Revision 1, dated May 15, 1995. If a visual inspection is conducted, it must be performed 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; or if the horizontal stabilizer primary trim motor has been modified previously in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; 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 and has not been modified previously in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; prior to further flight, accomplish either paragraph (b)(2)(i) or (b)(2)(ii) of this AD. \n\n\t\t\t(i)\tReplace the motor in accordance with the McDonnell Douglas alert service bulletin. Or \n\n\t\t\t(ii)\tModify the motor in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; and install the modified motor in accordance with the McDonnell Douglas alert service bulletin. \n\n\t(c)\tAs of six months after the effective date of this AD, no person shall install, on any airplane, a horizontal stabilizer primary trim motor identified with one of the suspect serial numbers listed in McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994, or Revision 1, dated May 15, 1995; unless that motor has been modified in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995. \n\n\t(d)\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 3: 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(e)\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(f)\tThe inspection and replacement shall be done in accordance with McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994; and McDonnell Douglas MD-80 Alert Service Bulletin A27-342, Revision 1, dated May 15, 1995, which contains the following list of effective pages: \n\n\n\nPage Number\nRevision Level\nShown on Page\nDate\nShown on Page \n1-5, 7-10\n1\nMay 15, 1995\n6\nOriginal\nAugust 4, 1994\n\nThe modification shall be done in accordance with Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995. The incorporation by reference of McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August 4, 1994, was approved previously by the Director of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of April 21, 1995 (60 FR 15034, March 22, 1995). The incorporation by reference of McDonnell Douglas MD-80 Alert Service Bulletin A27-342, Revision 1, dated May 15, 1995; and Sundstrand Service Bulletin 9590-27-012, dated August 8, 1995; 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); or from Sundstrand Aerospace, 4747 Harrison Avenue, P.O. Box 7002, Rockford, Illinois 61125-7002. 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, 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(g)\tThis amendment becomes effective on April 3, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 95-06-04, amendment 39-9174 (60 FR 15034, March 22, 1995), which is applicable to McDonnell Douglas Model DC-9-80 series airplanes, was published in the Federal Register on September 26, 1995 (60 FR 49525). That action proposed to continue to require the current inspections and replacement of certain suspect horizontal stabilizer primary trim motors. That action also proposed to expand the applicability of the current AD to include additional affected airplanes. \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\tThree commenters support the proposal. \n\n\tOne commenter requests that the proposal be revised to allow operators to conduct a records search, rather than a visual inspection, to determine if the subject motor is installed on the airplane. This commenter, an operator of affected airplanes, states that it tracks the subject motors by the manufacturer's serial number, which enables it to identify quickly the location of any of the subject motors at any given time. Therefore, the commenter considers that, in lieu of requiring it (and possibly other operators) to apply for an alternative method of compliance with the AD, the final rule should provide for this alternative action. \n\n\tThe FAA concurs with the commenter's request. The final rule has been revised to provide for the option of conducting a records search to determine if the motor installed on the airplane is identified with one of the suspect serial numbers. \n\n\tTwo commenters request that the proposed AD be revised to preclude operators from having to reinspect for units that were previously modified and re-identified (i.e., in accordance with Sundstrand Service Bulletin 9590-27-012). One of these commenters points out that these units require an overhaul every 3,500 hours; at that time they are removed from the airplane and, after overhaul, may be installed on a different airplane or placed in spare status (pending installation on another airplane). One commenter points out that the proposed AD does not take into account the situation where a unit originally installed on an airplane subject to AD 95-06-04 may be removed from that airplane and later installed on another airplane that is subject to the proposed AD. If this situation occurs, the commenter is concerned that operators will be required to duplicate inspections and other actions unnecessarily. \n\n\tThe FAA concurs that some clarification is necessary. As for motors modified (and re- identified) in accordance with Sundstrand Service Bulletin 9590-27-012, the final rule allows for their installation on airplanes that are subject to either AD 95-06-04 or this new AD. If a modified unit is installed on any of these airplanes no further action, including any duplicating"re- identification," is required by the AD. In order to make this eminently clear, the FAA has revised paragraphs (a) and (b) of the final rule to specify that, if the trim motor installed on the airplane has been modified previously in accordance with the applicable Sundstrand service bulletin, no further action is required. \n\n\tAs for the possibility of suspect units being installed as spares, the FAA is not certain that this possibility would occur, since the FAA has been advised that apparently all motors affected by AD 95-06-04 have been modified. However, the FAA has added paragraph (c) to the final rule to preclude the future installation, on any airplane, of a motor having one of the suspect serial numbers. \n\n\tAs for duplicating inspections, as discussed above, the FAA has revised the final rule to allow operators to conduct a records search, in lieu of a visual inspection, to determine if the suspect motor is installed. A records search would expedite the determinationas to whether or not a suspect unit is installed; it would also be far less expensive to accomplish than a visual inspection of the airplane. \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 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 142 Model DC-9-80 series airplanes of the affected design in the worldwide fleet. The FAA estimates that a total of 73 airplanes of U.S. registry will be affected by this proposed AD. \n\n\tThe inspection of the horizontal stabilizer primary trim motor is expected to take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this requirement is estimated to be $60 per airplane.The inspection specified in this rule previously was required by AD 95-06-04, which was applicable to approximately 13 U.S.-registered airplanes. Based on the figures discussed above, the cost impact of the current inspection requirements of that AD on U.S. operators of those 13 airplanes is estimated to be $780. In consideration of the compliance time and effective date of AD 95-06-04, the FAA assumes that the operators of the 13 airplanes subject to that AD have already initiated the required actions. This new AD action will add no new costs associated with those airplanes. \n\n\tThis new AD is applicable to approximately 60 additional airplanes. Based on the figures discussed above, the new (inspection) costs to U.S. operators that will be imposed by this new AD are estimated to be $3,600. This figure is based on assumptions that no operator of these additional airplanes 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\tShould an operator elect to replace a suspect motor, that action will require 5 work hours to accomplish, at an average labor rate of $60 per work hour. Required parts will be provided by Sundstrand Electric Power Systems (the manufacturer of the horizontal stabilizer primary trim motors) at no charge to operators. Based on these figures, the cost impact on U.S. operators for the replacement of a suspect motor is estimated to be $300 per airplane. \n\n\tShould an operator elect to modify a suspect motor, that action will require 4 work hours to disassemble, modify, reassemble, and test the motor (excluding removal and reinstallation of the motor from the airplane). The average labor rate is $60 per work hour. Required parts will be provided by Sundstrand at no charge to operators. Based on these figures, the cost impact on U.S. operators for the modification of a suspect motor is estimated to be $240 per airplane. \n\n\tTheregulations 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 RulesDocket 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\n Adoption 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: \n\nAuthority: 49 USC 106(g), 40113, 44701. \n\n§ 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by removing amendment 39-9174 (60 FR 15034, March 22, 1995), and by adding a new airworthiness directive (AD), amendment 39-9525, to read as follows: