AD 96-16-01

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10-10 and DC-10-15 series airplanes, that 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 a report 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 main landing gear (MLG) as a result of chrome flaking and severe corrosion on the bearing surface and in the mechanical fuse.

Final rule.

96-16-01 MCDONNELL DOUGLAS: Amendment 39-9701. Docket 96-NM-39-AD. \n\n\tApplicability: Model DC-10-10 and DC-10-15 series airplanes, as listed in McDonnell Douglas Service Bulletin DC10-32-241, dated December 13, 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 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 (c) 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 prevent premature failure of the trunnion bolts and subsequent collapse of the main landing gear (MLG), accomplish the following: \n\n\t(a)\tFor airplanes on which the forward trunnion bolts, part number (P/N) ARG7557-501, 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 or verification required by paragraph (a)(1) or (a)(2), respectively, of this AD: Within 18 months after the effective date of this AD, accomplish either paragraph (a)(1) or (a)(2) of this AD, in accordance with McDonnell Douglas Service Bulletin DC10-32-241, dated December 13, 1995. \n\n\t\t(1)\tRemove 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 surfacesare 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 (a)(1)(ii)(A) or (a)(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 Component Maintenance Manual (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. \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)\tVerify whether the forward trunnion bolts, P/N ARG7557-501, 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 (a)(1)(ii)(A) or (a)(1)(ii)(B) of this AD in accordance with the service bulletin. \n\n\t(b)\tFor airplanes other than those identified in paragraph (a) of this AD: Within 18 months after the effective date of this AD, verify whether the forward trunnion bolts, P/N ARG7557-501, 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(1)\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(2)\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 (b)(2)(i) or (b)(2)(ii) of this AD in accordance with McDonnell Douglas Service Bulletin DC10-32-241, dated December 13, 1995. \n\n\t\t\t(i)\tRemove the chrome plating on the trunnion bolt in accordance with the service bulletin; replace the plating in accordance with the Component Maintenance Manual (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 ACO, to make such a finding; and reinstall the reworked bolt in accordance with the service bulletin. Or \n\n\t\t\t(ii)\tReplace the trunnion bolt with a serviceable part in accordance with the service bulletin. \n\n\t(c)\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(d)\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(e)\tThe actions shall be done in accordance with McDonnell Douglas Service Bulletin DC10-32-241, dated December 13, 1995. 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, 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(f)\tThis amendment becomes effective on September 3, 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 DC-10-10 and DC-10-15 series airplanes was published in the Federal Register on April 10, 1996 (61 FR 15904). That action proposed to require a visual 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 two comments received. \n\n\tBoth commenters support the proposed rule. \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 as proposed. \n\nCost Impact \n\n\tThere are approximately 139 McDonnell Douglas Model DC-10-10 and DC-10-15 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 121 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 $7,260, 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\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 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\nAuthority: 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: