AD 98-24-17

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10-10, -30, and -40 series airplanes, that requires replacement of certain taper-lok attachments and forward trunnion bolts with new components that attach the left and right main landing gear (MLG) to each wing. This amendment is prompted by a report indicating that, due to overstrength of the forward trunnion bolt, an MLG broke away and ruptured a wing fuel tank while an airplane was being operated off the runway. The actions specified by this AD are intended to ensure that the MLG separates from the wing when it is subjected to unpredictable overloads during abnormal operations, and to prevent consequent primary structural damage to the airplane.

Final rule.

98-24-17 MCDONNELL DOUGLAS: Amendment 39-10902. Docket 97-NM-14-AD. \n\n\tApplicability: Model DC-10-10, DC-10-30, and DC-10-40 series airplanes, certificated in any category; as listed in the following McDonnell Douglas service bulletins: \n\nMcDonnell Douglas DC-10 Service Bulletin 57-78, Revision 1, dated August 26, 1986; \n\nMcDonnell Douglas DC-10 Service Bulletin 57-79, Revision 1, dated September 21, 1979, as revised by McDonnell Douglas DC-10 Service Bulletin Change Notification 57-79, dated January 23, 1980; and \n\nMcDonnell Douglas DC-10 Service Bulletin 57-82, dated February 19, 1980. \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 foran alternative method of compliance in accordance with paragraph (g) 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 ensure that the main landing gear (MLG) separates from the wing when it is subjected to unpredictable overloads during abnormal operations, and to prevent consequent primary structural damage to the airplane, accomplish the following: \n\n\t(a)\tFor Model DC-10-10 series airplanes, as listed in McDonnell Douglas DC-10 Service Bulletin 57-78, Revision 1, dated August 26, 1986: Within 5 years after the effective date of this AD, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD, in accordance with the service bulletin. \n\n\t\t(1)\tReplace 24 TL taper-lok attachments that attach the left and right MLG attach fitting assemblies on each wing with heat-treat TLH taper-lok attachments in accordance with the service bulletin. And \n\n\t\t(2)\tReplace each forward trunnion bolt on the left and right MLG of each wing with a "zero margin" trunnion bolt in accordance with the service bulletin. \n\n\tNOTE 2: Replacement of taper-lok attachments and forward trunnion bolts accomplished prior to the effective date of this AD in accordance with McDonnell Douglas DC-10 Service Bulletin 57-78, dated February 19, 1980, is considered acceptable for compliance with the requirements of paragraphs (a)(1) and (a)(2) of this AD. \n\n\t(b)\tFor Model DC-10-10 series airplanes, as listed in McDonnell Douglas DC-10 Service Bulletin 57-79, Revision 1, dated September 21, 1979, as revised by McDonnell Douglas DC-10 Service Bulletin Change Notification 57-79, dated January 23, 1980: Within 5 years after the effective date of this AD, replace each 1-1/2-inch-diameter bolt and bushing that attach the left and right MLG attach fitting and rear spar of each wing with a 1-1/4-inch-diameter bolt, and install bolt retainers, in accordance with the service bulletin and service bulletin change notification. \n\n\tNOTE 3: Replacement of 1-1/2-inch-diameter bolts and installation of bolt retainers prior to the effective date of this AD in accordance with McDonnell Douglas DC-10 Service Bulletin 57-79, dated June 5, 1979, are considered acceptable for compliance with the requirements of paragraph (b) of this AD. \n\n\t(c)\tFor Model DC-10-30 and DC-10-40 series airplanes: Except as provided by paragraph (d) of this AD, within 5 years after the effective date of this AD, accomplish the requirements of paragraph (c)(1) or (c)(2) of this AD, as applicable, in accordance with McDonnell Douglas DC-10 Service Bulletin 57-82, dated February 19, 1980. \n\n\t\t(1)\tFor airplanes identified as Groups I and II in the service bulletin: Replace each forward trunnion bolt on the left and right MLG of each wing with a "zero margin" forward trunnion bolt; replace each 1-1/2-inch-diameter bolt and bushing that attach the left and right MLG attach fitting and rear spar of each wing with a 1-1/4-inch-diameter bolt, and install bolt retainers, in accordance with the service bulletin. \n\n\t\t(2)\tFor airplanes identified as Group III in the service bulletin: Replace each forward trunnion bolt on the left and right MLG of each wing with a "zero margin" trunnion bolt in accordance with the service bulletin. \n\n\t(d)\tFor Model DC-10-30 and DC-10-40 series airplanes: Installation of a trunnion bolt having part number (P/N) ARG7558-501 or P/N ARG7558-507 on the MLG, in accordance with AD 96-03-05, amendment 39-9502, constitutes terminating action for the requirement to replace the trunnion bolts for that landing gear, as required in paragraphs (c)(1) and (c)(2) of this AD. \n\n\t(e)\tFor Model DC-10-30 and DC-10-40 series airplanes: Replacement of the trunnion bolts with a serviceable part in accordance with paragraph (c)(1)(ii)(B) of AD 96-03-05, amendment 39-9502, constitutes terminating action for the requirement to replace the trunnion bolts, as required in paragraphs (c)(1) and (c)(2) of this AD. \n\n\t(f)\tFor Model DC-10-10 series airplanes: Replacement of the trunnion bolts with a serviceable part in accordance with paragraph (a)(1)(ii)(B) of AD 96-16-01, amendment 39-9701, constitutes terminating action for the requirement to replace the trunnion bolts, as required in paragraph (a)(2) of this AD. \n\n\t(g)\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 4: Informationconcerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\n\t(h)\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(i)\tThe actions shall be done in accordance with McDonnell Douglas DC-10 Service Bulletin 57-78, Revision 1, dated August 26, 1986; McDonnell Douglas DC-10 Service Bulletin 57-79, Revision 1, dated September 21, 1979, as revised by McDonnell Douglas DC-10 Service Bulletin Change Notification 57-79, dated January 23, 1980; and McDonnell Douglas DC-10 Service Bulletin 57-82, dated February 19, 1980. 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 The Boeing Company, Douglas Products Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). 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, 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(j)\tThis amendment becomes effective on December 29, 1998.

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 DC-10-10, -30, and -40 series airplanes was published in the Federal Register on January 22, 1998 (63 FR 3267). That action proposed to require replacement of certain taper-lok attachments and forward trunnion bolts with new components that attach the left and right main landing gear (MLG) to each wing. \n\nComments Received \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\nSupport for the Proposal \n\n\tSeveral commenters support the proposed rule. \n\nRequest to Extend Compliance Time \n\n\tOne commenter requests that the compliance time for accomplishing the proposed replacement of certain taper-lok attachments and forward trunnion bolts be extended from the proposed 5 years to 6 years. The commenter states that such an extension will allow the replacement to be accomplished during a regularly scheduled heavy maintenance visit, and thereby eliminate any additional expenses that would be associated with special scheduling. The FAA does not concur. In developing an appropriate compliance time for this action, the FAA considered not only the degree of urgency associated with addressing the unsafe condition, the availability of required parts, normal maintenance schedules, and the significant amount of time that is necessary to perform the replacement. In consideration of all of these factors, the FAA has determined that further delay of this replacement is not appropriate. However, under the provision of paragraph (g) of the final rule, the FAA may approve requests for adjustments to the compliance time if sufficient data are submitted to substantiate that such an adjustment would provide an acceptable level of safety. \n\nRequest That CreditBe Given for Previous Replacements \n\n\tOne commenter recommends that the FAA revise the proposed rule to specify that operators will be given "credit" for having previously accomplished the actions specified in the proposed rule. The FAA does not consider that a change to the final rule is necessary. Operators are given credit for work previously performed by means of the phrase in the "Compliance" section of the AD that states, "Required as indicated, unless accomplished previously." Therefore, in the case of this AD, if the required replacement has been accomplished prior to the effective date of this AD, this AD does not require that it be repeated. \n\nRequest That the Forward Trunnion Bolt Be Inspected \n\n\tOne commenter requests that the FAA ensure that the "forward" trunnion bolt is replaced, not the "aft" trunnion bolt. The FAA finds that the forward trunnion bolt was addressed correctly in the proposed rule. No change to the final rule is necessary. \n\nRequest to Ensure That Other AD's Do Not Conflict with This AD \n\n\tOne commenter requests that the FAA ensure that requirements of AD 96-16-01, amendment 39-9701 (61 FR 39312, July 29, 1996), and AD 96-03-05, amendment 39-9502 (61 FR 5281, February 12, 1996), do not conflict with the requirements of the proposed AD. The commenter states that these two AD's already require installation and modification of the trunnion bolts in accordance with McDonnell Douglas Service Bulletins DC10-57-78 and DC10-57-82. The commenter also states that these AD's have introduced a new trunnion bolt part number for Model DC-10-30 series airplanes (reference McDonnell Douglas Service Bulletin DC10-32-239, Revision 1) that is not included in Service Bulletin DC10-57-82. \n\n\tThe FAA finds that clarification is necessary. Both AD 96-16-01 and AD 96-03-05 require either removing the chrome plating on the trunnion bolt, replacing the plating, and reinstalling the reworked bolt; or replacing the trunnion bolt with a serviceable bolt. Replacement of the subject trunnion bolts in accordance with either of these AD's constitutes terminating action for the requirement to replace the trunnion bolts, as required by paragraphs (a)(2), (c)(1), and (c)(2) of this AD. The FAA has revised the final rule by including new paragraphs (e) and (f) to clarify this point. Paragraph (d) of this AD also addresses a similar point for Model DC-10-30 and DC-10-40 series airplanes. \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 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\nCost Impact \n\nFor McDonnell Douglas Model DC-10-10 series airplanes: \n\n\tThere are approximately 119 Model DC-10-10 series airplanes of the affected design in the worldwide fleet, and 108 airplanes of U.S. registry that will be affected by the requirements for replacement of taper-lok attachments and forward trunnion bolts. The FAA estimates that it will take approximately 462 work hours per airplane to accomplish these required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $47,000 per airplane. Based on these figures, the cost impact of these required actions on U.S. operators is estimated to be $8,069,760, or $74,720 per airplane. \n\n\tThere are approximately 111 Model DC-10-10 series airplanes of the affected design in the worldwide fleet, and 82 airplanes of U.S. registry that will be affected by the requirements for replacement of larger attach bolts and installation of bolt retainers. The FAA estimates that it will take approximately 500 work hours per airplane to accomplish these required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $11,734 per airplane. Based on these figures, the cost impact of these required actions on U.S. operators is estimated to be $3,422,188, or $41,734 per airplane. \n\nFor McDonnell Douglas Model DC-10-30 and DC-10-40 series airplanes: \n\n\tThere are approximately 168 Model DC-10-30 and DC-10-40 series airplanes of the affected design in the worldwide fleet, and 82 airplanes of U.S. registry that are identified as Groups I and II airplanes in the relevant service bulletins and that will be affected by the requirements for replacement of larger attach bolts, installation of bolt retainers, and replacement of forward trunnion bolts. The FAA estimates that it will take approximately 576 work hours per airplane to accomplish these required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $20,000 per airplane. Based on these figures, the cost impact of these required actions on U.S. operators is estimated to be $4,473,920, or $54,560 perairplane. \n\n\tThere are approximately 20 Model DC-10-30 and DC-10-40 series airplanes of the affected design in the worldwide fleet, and 6 airplanes of U.S. registry that are identified as Group III airplanes in the relevant service bulletins and that will be affected by the requirements for replacement of forward trunnion bolts. The FAA estimates that it will take approximately 76 work hours per airplane to accomplish this required action, and that the average labor rate is $60 per work hour. Required parts will cost approximately $15,800 per airplane. Based on these figures, the cost impact of this required action on U.S. operators is estimated to be $122,160, or $20,360 per airplane. \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. \n\n\tHowever, the FAA has been advised that the following actions have been accomplished on Model DC-10-10 series airplanes in accordance with the requirements of this AD: \n\nTaper-lok attachments and forward trunnion bolts have been replaced on 77 U.S.-registered airplanes. Therefore, the future economic cost impact of those actions on U.S. operators is now only $2,316,320. \n\nLarger attach bolts have been replaced and bolt retainers have been installed on 77 U.S.-registered airplanes. Therefore, the future economic cost impact of those actions on U.S. operators is now only $208,670. \n\n\tThe FAA also has been advised that the following actions have been accomplished on Model DC-10-30 and DC-10-40 series airplanes in accordance with the requirements of this AD: \n\nForward trunnion bolts and larger attach bolts have been replaced and bolt retainers have been installed on 40 U.S.-registered airplanes identified as Groups I and II airplanes in the relevant service bulletins. Therefore, the future economic cost impact of those actions onU.S. operators is now only $2,291,520. \n\nForward trunnion bolts have been replaced on 3 U.S.-registered airplanes identified as Group III airplanes in the relevant service bulletins. Therefore, the future economic cost impact of this action on U.S. operators is now only $61,080. \n\nRegulatory Impact \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 \nunder 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 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: Authority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: