AD 96-10-17

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10-10, -15, and -30 series airplanes and KC-10A (military) airplanes, that requires inspections to detect cracks of the upper aft mating bolt hole of the wing pylon truss fittings, and various follow-on actions. This amendment is prompted by reports of cracks found in the upper aft mating bolt hole of the wing pylon truss fitting located near the engine forward mount on Model DC-10-30 series airplanes, which were caused by fatigue-related stress. The actions specified by this AD are intended to prevent fatigue-related cracking, which could lead to failure of the fitting, separation of a portion of the engine forward mount truss from the pylon, and consequent separation of the engine from the airplane.

Final rule.

96-10-17 MCDONNELL DOUGLAS: Amendment 39-9624. Docket 95-NM-108-AD. \n\n\tApplicability: Model DC-10-10, -15, and -30 series airplanes and KC-10A (military) airplanes; as listed in McDonnell Douglas DC-10 Service Bulletin 54-108, dated February 9, 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 fatigue-related cracking, which could lead to failure of the pylon truss fitting, separation of a portion of the engine forward mount truss from the pylon, and consequent separation of the engine from the airplane, accomplish the following: \n\n\t(a)\tFor Model DC-10-15, and -30 series airplanes and KC-10A (military) airplanes: Prior to the accumulation of 10,000 total landings on the pylon truss fitting or within 1,000 landings on the pylon truss fitting after the effective date of this AD, whichever occurs later, perform either an ultrasonic inspection or an eddy current inspection, as applicable, to detect cracks of the upper aft mating bolt hole of the wing pylon truss fittings, in accordance with McDonnell Douglas DC-10 Service Bulletin 54-108, dated February 9, 1995. \n\n\t\t(1)\tIf no cracks are detected, repeat the inspections in accordance with paragraph (a)(1)(i) or (a)(1)(ii), as applicable: \n\n\t\t\t(i)\tIf inspecting using ultrasonic techniques, repeat inspection at intervals not to exceed 5,000 landings. \n\n\t\t\t(ii)\tIf inspecting using eddy current techniques, repeat inspection at intervals not to exceed 8,000 landings. \n\n\t\t(2)\tAccomplishment of the actions specified in paragraphs (a)(2)(i), (a)(2)(ii), and (a)(2)(iii) constitutes terminating action for the repetitive inspections required by paragraph (a)(1) of this AD: \n\n\t\t\t(i)\tAccomplish the preventative modification in accordance with Condition 1 (bushing not installed), Option III, or Condition 2 (bushing installed), Option II, of the service bulletin, as applicable. And \n\n\t\t\t(ii)\tPrior to the accumulation of 10,000 total landings on the pylon truss fitting following accomplishment of the modification, perform an ultrasonic inspection to detect cracks of the upper aft mating bolt hole of the wing pylon truss fittings, in accordance with the service bulletin. And \n\n\t\t\t(iii)\tThereafter, repeat the ultrasonic inspection at intervals not to exceed 5,000 landings on the pylon truss fitting. \n\n\t\t(3)\tIf any crack is found in the pylon truss fitting during any inspection required by this paragraph, prior to further flight, repair it in accordance with the service bulletin. At the times specified in the service bulletin, perform follow-on actions in accordance with the service bulletin. In all cases, where the service bulletin indicates "contact Douglas for disposition," the repair must be accomplished in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\t(b)\tFor Model DC-10-10 series airplanes: Prior to the accumulation of 17,000 total landings on the pylon truss fitting or within 1,500 landings on the pylon truss fitting after the effective date of this AD, whichever occurs later, perform either an ultrasonic inspection or an eddy current inspection, as applicable, to detectcracks of the upper aft mating bolt hole of the wing pylon truss fittings, in accordance with McDonnell Douglas DC-10 Service Bulletin 54-108, dated February 9, 1995. \n\n\t\t(1)\tIf no cracks are detected, repeat the inspections in accordance with paragraph (b)(1)(i) or (b)(1)(ii), as applicable: \n\n\t\t\t(i)\tIf inspecting using ultrasonic techniques, repeat the inspection at intervals not to exceed 10,000 landings. \n\n\t\t\t(ii)\tIf inspecting using eddy current techniques, repeat the inspection at intervals not to exceed 15,000 landings. \n\n\t\t(2)\tAccomplishment of the actions specified in paragraphs (b)(2)(i), (b)(2)(ii), and (b)(2)(iii) constitutes terminating action for the repetitive inspections required by paragraph (b)(1) of this AD: \n\n\t\t\t(i)\tAccomplish the preventative modification in accordance with Condition 1 (bushing not installed), Option III, or Condition 2 (bushing installed), Option II, of the service bulletin, as applicable. And \n\n\t\t\t(ii)\tPrior to the accumulation of 18,000 total landings on the pylon truss fitting following accomplishment of the modification, perform an ultrasonic inspection to detect cracks of the upper aft mating bolt hole of the wing pylon truss fittings, in accordance with the service bulletin. And \n\n\t\t\t(iii)\tThereafter, repeat the ultrasonic inspection at intervals not to exceed 10,000 landings on the pylon truss fitting. \n\n\t\t(3)\tIf any crack is found in the pylon truss fitting during any inspection required by this paragraph, prior to further flight, repair it in accordance with the service bulletin. At the times specified in the service bulletin, perform follow-on actions in accordance with the service bulletin. In all cases, where the service bulletin indicates "contact Douglas for disposition," the repair must be accomplished in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \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 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(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 DC-10 Service Bulletin 54-108, dated February 9, 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, 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(f)\tThis amendment becomes effective on June 20, 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, -15, and -30 series airplanes and KC-10A (military) airplanes series airplanes was published in the Federal Register on September 27, 1995 (60 FR 49809). That action proposed to require repetitive ultrasonic or eddy current inspections to detect cracks of the upper aft mating bolt hole of the wing pylon truss fittings, and various follow-on actions. \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\tTwo commenters support the proposed rule. \n\nRequest for Extension of Compliance Time for Initial Inspection \n\n\tOne commenter requests that the compliance time for the initial inspection be extended from the proposed 1,000 landings to 1,200 landings for Model DC-10-30 series airplanes. The commenter states such a compliance time would follow the recommendations of McDonnell Douglas DC-10 Service Bulletin 54-108, dated February 9, 1995. The commenter also questions what data or analysis the FAA used to justify shortening the threshold to 1,000 landings. \n\n\tThe FAA does not agree with the commenter's request to extend the compliance time. The FAA points out that 1,000 landings is not the inspection "threshold," but a "grace period" that was established to preclude unnecessarily grounding airplanes that have exceeded the 10,000-landing threshold or will exceed it within 1,000 landings. In determining the appropriate "grace period" for this action, the FAA not only considered the degree of urgency associated with addressing the unsafe condition, but the amount of time necessary for operators to accomplish the required inspection and other factors affecting the ability of the operators to comply. In light of all these factors, the FAA finds the 1,000 landing "grace period" for initiating the required inspections to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.\n\nClarification of Requirements for Type of Inspection \n\n\tOne commenter points out that proposed paragraphs (a) and (b) indicate that operators are to perform either ultrasonic or eddy current inspections to detect the subject cracking. However, the commenter states that the initial and repetitive eddy current inspections are not an option if the upper aft and/or middle mating bolt hole(s) have bushings installed from previous rework, in accordance with McDonnell Douglas DC-10 Service Bulletin 54-108, dated February 9, 1995. \n\n\tThe FAA finds that clarification of this point is necessary. As paragraphs (a) and (b) of the proposed rule were worded, operators could incorrectly interpret the requirements as meaning that they have a choice between performing an ultrasonic inspection or an eddy current inspection for all configurations of the bolt holes. However, the intent of those requirements was to require operators to perform either an ultrasonic inspection or an eddy current inspection, as appropriate, depending upon the configuration of the subject area and as specified in the service bulletin. Therefore, the commenter is correct in noting that, for airplanes on which the upper aft and middle mating bolt holes have bushings installed from previous rework (Condition 2), operators must accomplish the inspection by using only the ultrasonic method. In light of this, the FAA has revised the wording of paragraphs (a) and (b) of the final rule to clarify this. \n\nClarification of Requirements for Repetitive Inspections \n\n\tThe same commenter asks if the repetitive ultrasonic inspection intervals are the same for bolt hole(s) that have bushings installed from previous rework as well as for bolt hole(s) that do not have bushings installed. \n\n\tThe FAA finds that clarification of this point is necessary. The FAA points out that, for certain Model DC-10-15, and -30 series airplanes, and KC-10A (military) airplanes, Service Bulletin 54-108 recommends that the compliance time for the repetitive ultrasonic inspections be accomplished at intervals of 4,000 landings if the bolts holes have bushings installed, and at intervals of 5,000 landings if the bolt holes do not have bushings installed. However, for those airplanes, paragraph (b)(1)(i) of the final rule differs from the recommendations of the service bulletin in that it requires a compliance time interval of 5,000 landings, whether or not the bolt holes have bushings installed. In developing an appropriate compliance time for that action, the FAA, along with McDonnell Douglas, reviewed the damage tolerance analysis of the bolt hole, and determined that the compliance time of 5,000 landings will not adversely affect safety. McDonnell Douglas is planning to revise Service Bulletin 54-108 in the future to be consistent with this AD. \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\n\tThere are approximately 376 McDonnell Douglas Model DC-10-10, -15, and -30 series airplanes and KC-10 (military) airplanes of the affected design in the worldwide fleet. The FAA estimates that 228 airplanes of U.S. registry will be affected by this AD, that it will take approximately 5 work hours 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 $68,400, or $300 per airplane, per inspection. \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 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: