AD 96-03-05

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 series airplanes and Model DC-10-30, DC-10-40, and KC-10A (military) airplanes. For Model MD-11 series airplanes, the AD requires an inspection to determine the serial number of the forward trunnion bolts on the main landing gear (MLG), and rework or replacement of the bolts, if necessary. For Model DC-10-30, DC-10-40, and KC-10A (military) airplanes, the AD requires an inspection for evidence of missing chrome and for corrosion on the chrome surfaces, or verification that the forward trunnion bolts have been chrome plated in a specific manner; and rework or replacement of the bolts, if necessary. This amendment is prompted by reports of chrome flaking on the bearing surface of the trunnion bolts due to improper cleaning of the base material prior to chrome plating. The actions specified by this AD are intended to prevent premature failure of the trunnion bolts and subsequent collapse of the MLG as a result of severe corrosion on the bearing surface and in the mechanical fuse due to chrome flaking.

Final rule.

96-03-05 MCDONNELL DOUGLAS: Amendment 39-9502. Docket 95-NM-39-AD. \n\n\tApplicability: Model MD-11 series airplanes, as listed in McDonnell Douglas MD-11 Service Bulletin 32-45, Revision 1, dated May 1, 1995; and Model DC-10-30, DC-10-40, and KC-10A (military) airplanes, as listed in McDonnell Douglas DC-10 Service Bulletin DC10-32-239, Revision 1, dated June 6, 1995, and Revision 2, dated January 8, 1996; 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 use the authority provided in paragraph (e) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminatesthe 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 premature failure of the trunnion bolts and subsequent collapse of the main landing gear (MLG), accomplish the following: \n\n\t(a)\tFor Model MD-11 series airplanes: Within 18 months after the effective date of this AD, perform a visual inspection to determine the serial number of the forward trunnion bolts, part number (P/N) ARG7558-503 or ARG7558-505, on the right and left MLG's, in accordance with McDonnell Douglas MD-11 Service Bulletin 32-45, Revision 1, dated May 1, 1995. \n\n\t\t(1)\tIf the serial number of the trunnion bolt is STR0217, STR0232, STR0237 through STR0242 inclusive, or STR0244 through STR0284 inclusive; or if the trunnion bolt has been chrome plated in accordance with the Component Maintenance Manual (CMM), Chapter 20-10-02, Revision 31, dated September 1, 1991, since original manufacture: No further action is required by this AD. \n\n\t\t(2)\tFor trunnion bolts other than those identified in paragraph (a)(1) of this AD: Prior to further flight, remove the chrome plating on the trunnion bolt, replace the plating, and reinstall the reworked trunnion bolt; or replace the trunnion bolt with a serviceable part; in accordance with McDonnell Douglas MD-11 Service Bulletin 32-45, Revision 1, dated May 1, 1995. \n\n\t(b)\tFor Model MD-11 series airplanes: Installation of a trunnion bolt having P/N ARG7558-509 or ARG7008-511 on the MLG constitutes terminating action for the requirements of this AD for that MLG. \n\n\t(c)\tFor Model DC-10-30, DC-10-40, and KC-10A (military) airplanes: Within 18 months after the effective date of this AD, accomplish either paragraph (c)(1) or (c)(2) of this AD, as applicable, in accordance with McDonnell Douglas DC-10 Service Bulletin DC10-32-239, Revision 1, dated June 6, 1995, or Revision 2, dated January 8, 1996. \n\n\t\t(1)\tFor airplanes on which the forward trunnion bolts, P/N ARG7558-501, installed on the left and right MLG's, have accumulated 6,000 or more total flight hours or 2,000 or more total flight cycles as of the date of the inspection: Remove the bolts and perform a visual inspection for evidence of missing chrome and for corrosion on the chrome surfaces, in accordance with the service bulletin. \n\n\t\t\t(i)\tIf no evidence of missing chrome and no corrosion on the chrome surfaces are found, no further action is required by this AD. \n\n\t\t\t(ii)\tIf any evidence of missing chrome or any corrosion on the chrome surfaces is found, prior to further flight, accomplish either paragraph (c)(1)(ii)(A) or (c)(1)(ii)(B) of this AD. \n\n\t\t\t\t(A)\tRemove the chrome plating on the trunnion bolt in accordance with the service bulletin; replace the plating in accordance with the CMM, Chapter 20-10-02, Revision 31, dated September 1, 1991, or in accordance with a method approved by a McDonnell Douglas Designated Engineering Representative (DER) who has been given a special delegation by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, to make such a finding; and reinstall the reworked bolt in accordance with the service bulletin. Or \n\n\t\t\t\t(B)\tReplace the trunnion bolt with a serviceable part in accordance with the service bulletin. \n\n\t\t(2)\tFor airplanes other than those identified in paragraph (c)(1) of this AD: Verify whether the forward trunnion bolts, P/N ARG7558-501, installed on the left and right MLG's, have been chrome plated since original manufacture, in accordance with the CMM, Chapter 20-10-02, Revision 31, dated September 1, 1991, or in accordance with a method approved by a McDonnell Douglas DER who has been given a special delegation by the Manager, Los Angeles ACO, to make such a finding. \n\n\t\t\t(i)\tIf the bolts have been chrome plated since original manufacture, in accordance with the CMM, Chapter 20-10-02, Revision 31, dated September 1, 1991, or in accordance with a method approved by a McDonnell Douglas DER who has been given a special delegation by the Manager, Los Angeles ACO, to make such a finding: No further action is required by this AD. \n\n\t\t\t(ii)\tIf any bolt has not been chrome plated since original manufacture, in accordance with the CMM, Chapter 20-10-02, Revision 31, dated September 1, 1991, or in accordance with a method approved by a McDonnell Douglas DER who has been given a special delegation by the Manager, Los Angeles ACO, to make such a finding: Prior to further flight, accomplish the requirements of either paragraph (c)(1)(ii)(A) or (c)(1)(ii)(B) of this AD in accordance with the service bulletin. \n\n\t(d)\tFor Model DC-10-30, DC-10-40, and KC-10A (military) airplanes: Installation of a trunnion bolt having P/N ARG7558-507 on the MLG constitutes terminating action for the requirements of this AD for that MLG. \n\n\t(e)\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 ACO. 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(f)\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(g)\tThe actions shall be done in accordance with McDonnell Douglas MD-11 Service Bulletin 32-45, Revision 1, dated May 1, 1995; McDonnell Douglas DC-10 Service Bulletin DC10-32-239, Revision 1, dated June 6, 1995; and McDonnell Douglas DC-10 Service Bulletin DC10-32-239, Revision 2, dated January 8, 1996. 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, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Department C1-L51 (2-60). 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(h)\tThis amendment becomes effective on March 31, 1996.

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-11 series airplanes and Model DC-10-30, DC-10-40, and KC-10A (military) airplanes was published in the Federal Register on August 21, 1995 (60 FR 43417). For Model MD-11 series airplanes, that action proposed to require an inspection to determine the serial number of the forward trunnion bolts on the main landing gear (MLG), and rework or replacement of the bolts, if necessary. For Model DC-10-30, DC-10-40, and KC-10A (military) airplanes, that action proposed to require an inspection for evidence of missing chrome and for corrosion on the chrome surfaces, or verification that the forward trunnion bolts have been chrome plated in a specific manner; and rework or replacement of the bolts, if necessary. \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\tOne commenter supports the proposed rule. \n\n\tThree commenters request that the proposed rule be revised to specify that unmodified parts may not be installed as of 18 months after the effective date of the AD. (Paragraphs (b) and (d) of the proposed rule specify currently that unmodified parts may not be installed as of the effective date of the AD.) The commenters point out that, although these parts that are currently installed on an airplane would be allowed to continued in service for 18 months prior to modification, those same parts currently in stock as spares would not be permitted to be installed prior to modification, regardless of the cumulative time on the spare part or the circumstances under which an operator may need temporary use of unmodified spare parts. The commenters indicate that the availability of adequate numbers of replacement or modified parts is an issue in meeting the compliance date; in such cases, there is often a need to take low-time or zero-time spare parts and rotate them temporarily into installed positions so that the intent of the AD can be accomplished without disrupting service to the traveling and shipping public. Along this same line, one commenter asks whether the manufacturer has ensured that adequate quantities of the ARG7558 bolts are available for procurement in order to support "on condition" replacements necessary as a result of accomplishing the intent of the proposed rule. This commenter suggests that, if such bolts are not available, the FAA should delay implementation of the rule until an adequate stock exists. \n\n\tThe FAA concurs with the commenters' request. At the time the proposed rule was issued, the FAA had obtained information indicating that sufficient spare parts would be available to support a requirement that trunnion bolts not meeting the requirements of the AD not be installed on an airplane. However,since the issuance of the proposed rule, the manufacturer has advised the FAA that, due to delays in the manufacture of new trunnion bolts, only a limited number of replacement trunnion bolts would be available for use as spares at the time the AD becomes effective. The manufacturer has advised further that sufficient trunnion bolts will be available to support an 18-month compliance time. Accordingly, the FAA has removed paragraphs (b) and (d) from the final rule. \n\n\tOne commenter requests that installation of a trunnion bolt having part number ARG7558-507 be considered terminating action for the requirements of paragraph (c) of the proposed rule. The FAA concurs. Subsequent to the issuance of the proposed rule, the FAA determined that trunnion bolts having part numbers ARG7558-507 (for Model DC-10 series airplanes), ARG7558-509 (for Model MD-11 series airplanes), and ARG7008-511 (for Model MD-11 series airplanes) are superseding parts that have been manufactured using an improved process that eliminates the problem of severe corrosion on the bearing surface and mechanical fuse due to chrome flaking. These parts have been plated with nickel prior to being plated with chrome. In light of this information, the FAA has added new paragraphs (b) and (d) to this final rule to specify that installation of a trunnion bolt having part number ARG7558-507 on the MLG of Model DC-10 series airplanes, or part number ARG7558-509 or ARG7008-511 on the MLG of Model MD-11 series airplanes, constitutes terminating action for the requirements of this AD for that MLG. \n\n\tOne commenter asks if the FAA is considering including a provision in the AD to specify that visual inspections accomplished prior to the effective date of the final rule satisfy the requirement of paragraph (c) of the proposed AD. The FAA finds that no change to the final rule is necessary to provide such a provision. The AD contains a statement that reads, "Compliance: Required as indicated, unless accomplished previously." That statement provides credit for actions accomplished in accordance with the requirements of the AD prior to the effective date of the final rule. \n\n\tOne commenter requests that the economic impact information that was presented in the preamble to the notice be revised to increase the number of estimated necessary work hours from 1 to 33.5. The commenter states that when defective bolts are found the time required to accomplish the action proposed by this AD is approximately 33.5 work hours. The FAA does not concur with the commenter's request. The economic impact information presented is limited only to the cost of actions actually required by the rule (e.g., the inspection of the trunnion bolts). It does not consider the costs of "on condition" actions, e.g., "rework or replacement of the bolts, if necessary," since those actions would be required to be accomplished, regardless of AD direction, in order to correct an unsafe condition identified in an airplane and to ensure operation of that airplane in an airworthy condition, as required by the Federal Aviation Regulations. \n\n\tSubsequent to issuance of the proposal, McDonnell Douglas issued DC-10 Service Bulletin DC10-32-239, Revision 2, dated January 8, 1996. This revision is essentially identical to Revision 1, which was cited in the proposal as the appropriate source of service information; Revision 2 differs only in that it clarifies certain work instructions. The FAA has revised the final rule to include Revision 2 of the service bulletin as an additional source of service information. \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 414 Model MD-11 series airplanes and Model DC-10-30, DC-10-40, and KC-10A (military) airplanes of the affected design in the worldwide fleet. The FAA estimates that 196 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 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 cost impact of the AD on U.S. operators is estimated to be $11,760, or $60 per airplane. \n\n\tThe 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 accordancewith 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 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\n Authority: 49 USC 106(g), 40113, 44701. \n\n§ 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: