AD 98-20-08

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) series airplanes, that requires visual and eddy current inspections to detect cracking of the frame-to-longeron attachment area, the frame-to-skin shear clips at certain fuselage stations, and the fuselage bulkhead at the front spar of the engine pylon in the aft fuselage; and repair, if necessary. This AD also requires certain modifications which, when accomplished, will terminate the requirement for inspections. This amendment is prompted by reports indicating that fatigue cracking has occurred at those areas. The actions specified by this AD are intended to prevent such fatigue cracking, which could cause damage to adjacent structure and result in reduced structural integrity of the airplane.

Final rule.

98-20-08 MCDONNELL DOUGLAS: Amendment 39-10775. Docket 96-NM-244-AD. \n\n\tApplicability: Model DC-9-10, -20, -30, -40, -50 series airplanes, and C-9 (military) airplanes, 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 (f) 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 fatigue cracking of the frame-to-longeron attachment area and the frame-to-skin shear clips in the aft fuselage is detected and corrected in a timely manner so as to prevent damage to adjacent structure, which could result in loss of the capability of the engine pylon to support engine loads and possible separation of the engine from the airplane, accomplish the following: \n\n\t(a)\tFor airplanes listed in McDonnell Douglas Service Bulletin DC9-53-140, Revision 05, dated February 15, 1996: Perform an eddy current inspection to detect cracking of the longeron-to-frame attachment area and frame-to- skin shear clips of the aft fuselage, in accordance with the Accomplishment Instructions of that service bulletin at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. For airplanes subject to the requirements of paragraph (b) of this AD, the inspection shall be accomplished prior to, or in conjunction with, accomplishment of thatparagraph. Thereafter, repeat the inspection at intervals not to exceed 12,500 landings until the modification specified in paragraph (d) of this AD is accomplished. \n\n\t\t(1)\tFor airplanes that have not been previously inspected using visual inspection techniques in accordance with McDonnell Douglas Corrosion Prevention Control Program (CPCP), Document MDC-K4606, Revision 1, dated December 1990, perform the initial inspection prior to the accumulation of 30,000 total landings, or within 4,000 landings after the effective date of this AD, whichever occurs later. \n\n\t\t(2)\tFor airplanes that have been previously inspected using visual inspection techniques in accordance with McDonnell Douglas CPCP, perform the initial inspection within 8,500 landings after the previous visual inspection, or within 4,000 landings after the effective date of this AD, whichever occurs later. \n\n\t(b)\tFor airplanes listed in McDonnell Douglas DC-9 Service Bulletin 53-150, Revision 2, dated February 27, 1991: Perform a visual and eddy current inspection to detect cracking of the fuselage bulkhead at the front spar of the engine pylon of the aft fuselage, in accordance with the Accomplishment Instructions of that service bulletin, at the time specified in subparagraph (b)(1) or (b)(2) of this AD, as applicable. Thereafter, repeat the inspection at intervals not to exceed 4,000 landings until the modification specified in the service bulletin (and required by AD 96-10-11) is accomplished. \n\n\t\t(1)\tFor airplanes that have not been previously inspected using visual inspection techniques in accordance with McDonnell Douglas Corrosion Prevention Control Program (CPCP), Document MDC-K4606, Revision 1, dated December 1990, perform the initial inspection prior to the accumulation of 30,000 total landings, or within 4,000 landings after the effective date of this AD, whichever occurs later. \n\n\t\t(2)\tFor airplanes that have been previously inspected using visual inspection techniques in accordance with McDonnell Douglas CPCP, perform the initial inspection within 5,000 landings after the previous visual inspection, or within 4,000 landings after the effective date of this AD, which ever occurs later. \n\n\t(c)\tIf any cracking is detected during any inspection required by this AD, prior to further flight, repair the cracking in accordance with either McDonnell Douglas Service Bulletin DC9-53-140, Revision 05, dated February 15, 1996; or McDonnell Douglas DC-9 Service Bulletin 53-150, Revision 2, dated February 27, 1991; as applicable. \n\n\t(d)\tFor airplanes that are identified in McDonnell Douglas Service Bulletin DC9-53-140, Revision 05, dated February 15, 1996, but are not identified in Revision 3 of that service bulletin: Prior to the accumulation of 86,000 total landings, or within 4 years after the effective date of this AD, whichever occurs later, modify the longeron-to-frame attachment area and frame-to-skin shear clips, in accordance with McDonnell Douglas Service Bulletin DC9-53-140, Revision 05, dated February 15, 1996. Accomplishment of this modification constitutes terminating action for the repetitive inspection requirements of paragraph (a) of this AD. \n\n\tNOTE 2: Airplanes identified in Revision 3 of McDonnell Douglas Service Bulletin DC9-53-140 are required to accomplish the modification specified in paragraph (d) of this AD in accordance with the requirements of AD 96-10-11. \n\n\t(e)\tAccomplishment of the inspection requirements of this AD constitutes terminating action for the corresponding inspection requirements of AD 96-10-11 (which are required to be accomplished in accordance with McDonnell Douglas Service Bulletin DC9-53-140, Revision 3, dated March 12, 1986, and McDonnell Douglas DC-9 Service Bulletin 53-150, Revision 2, dated February 27, 1991). \n\n\t(f)\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(g)\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(h)\tThe actions shall be accomplished in accordance with McDonnell Douglas Service Bulletin DC9-53-140, Revision 05, dated February 15, 1996; and McDonnell Douglas DC-9 Service Bulletin 53-150, Revision 2, dated February 27, 1991, as applicable. 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, 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(i)\tThis amendment becomes effective on October 27, 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-9 and C-9 (military) series airplanes was published in the Federal Register on January 27, 1997 (62 FR 3837). That action proposed to require eddy current inspections to detect cracking of the frame-to-longeron attachment area, the frame-to-skin shear clips at certain fuselage stations, and the fuselage bulkhead at the front spar of the engine pylon in the aft fuselage; and repair, if necessary. That action also proposed to require certain modifications, which, when accomplished, would terminate the requirement for inspections. \n\nComments \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\nRequests Concerning Cost Impact Information \n\n\tThree commenters objectto the FAA's estimated cost of inspection and modification, and state that the time required to perform the actions is actually greater than that specified in the cost impact information of the proposed AD. One commenter requests that the compliance time for the proposed initial inspections to be accomplished in accordance with Revision 05 of McDonnell Douglas Service Bulletin DC9-53-140 and Revision 2 of McDonnell Douglas DC-9 Service Bulletin 53-150, and for the repetitive inspections to be accomplished in accordance with Revision 2 of McDonnell Douglas DC-9 Service Bulletin 53-150, be increased from 4,000 to 5,000 landings. According to the commenter, that increase would allow the inspections to be performed in conjunction with related scheduled maintenance activities and thereby lower the cost of compliance. \n\n\tAnother commenter requests that accurate cost impact figures be reflected in the final rule since it will have a significant economic impact on operators. One other commenter disagrees with the labor estimates provided in the proposal, and notes that the terminating action (modification) figures omit access and close up time. The commenter does not object to the terminating action, but suggests that the FAA withdraw the proposed AD until the proper figures are developed to ascertain financial impact. \n\n\tThe FAA does not concur with these commenters' requests. With regard to the commenter's request to extend the compliance times for economic reasons, the FAA has determined that 4,000 landings for the initial and repetitive inspections is the maximum number of landings in which the safety of the affected airplanes can be ensured. The commenters provided no data indicating that extending the compliance time would result in an acceptable level of safety. Additionally, the number of work hours necessary to accomplish the required actions was provided to the FAA by the manufacturer based on the best data available to date. The FAA acknowledges thatthe cost impact information, below, describes only the "direct" costs of the specific actions required by this AD. The FAA recognizes that, in accomplishing the requirements of any AD, operators may incur "incidental" costs in addition to the "direct" costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs, such as the time required to gain access and close up; planning time; or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate. \n\nClarification of Requirements of This AD \n\n\tOne commenter notes that the airplanes affected by paragraph (a) of the proposal should be clarified to exclude airplanes covered by paragraph (b) by adding the phrase "except as provided by paragraph (b)." Additionally, the commenter states that the requirement for only paragraph (a)(1), to be accomplished prior to or in conjunction with paragraph (a)(2), is unacceptable, since it negates the inspection provision allowed in paragraph (b). The commenter suggests that compliance with either paragraph (a)(1) or (b) is acceptable and should be so stated. \n\n\tTwo commenters also note that the compliance time for the initial inspection in accordance with McDonnell Douglas DC-9 Service Bulletin 53-150 should include provisions for airplanes inspected previously in accordance with McDonnell Douglas Corrosion Prevention Control Program (CPCP). \n\n\tThe FAA finds that clarification of these requirements is necessary. The proposed AD does not clearly specify that, for airplanes subject to the requirements of paragraph (b), the actions specified in paragraph (a)(1) of the proposed AD are not required since those actions are the same. Additionally, although the proposed AD specifies that the requirements of paragraph (a)(1) must be accomplished prior to or in conjunction with paragraph (a)(2), if an operator accomplishes paragraph (b)of the proposal, the requirements of that paragraph also must be accomplished prior to or in conjunction with paragraph (a)(2) of the proposed AD. The FAA concurs that if inspections have been accomplished previously in accordance with the CPCP, credit should be given to operators in order to extend the compliance time for accomplishment of McDonnell Douglas DC-9 Service Bulletin 53-150, as specified in paragraphs (a)(2) and (d) of the proposed rule. \n\n\tIn order to address these considerations, this final rule has been reformatted as follows: \n\n\t-\tParagraph (a) of the final rule addresses only airplanes listed in McDonnell Douglas Service Bulletin DC9-53-140, including those that have been inspected previously using visual techniques in accordance with CPCP. This new paragraph (a) requires accomplishment of the inspections required in Service Bulletin DC9-53-140. \n\n\t-\tParagraph (b) of the final rule addresses only airplanes listed in McDonnell Douglas DC-9 Service Bulletin 53-150, including those that have been inspected previously using visual techniques in accordance with CPCP. This new paragraph (b) requires accomplishment of the inspections required in DC-9 Service Bulletin 53-150. \n\n\t-\tParagraphs (a) and (b) of this final rule address all requirements contained previously in paragraphs (a), (b), (c), and (d) of the proposed rule. Requirements of This AD and AD 96-10-11 \n\n\tThe commenters point out conflicts between the requirements of this proposed AD and AD 96-10-11. Two commenters suggest that the proposed AD should state clearly that it either supersedes the modification requirements of AD 96-10-11 (in accordance with McDonnell Douglas Service Bulletin DC9-53-140 and McDonnell Douglas DC-9 Service Bulletin 53-150), or that it provides an alternative method of compliance with that AD. \n\n\tOne commenter recommends changing the proposal to require only the repetitive inspections or, alternatively, to remove the actions specified in the two servicebulletins discussed previously from AD 96-10-11. The commenter states that the potential overlap of compliance times specified in this proposed AD and in AD 96-10-11 will cause confusion and could result in airplanes being out of compliance. \n\n\tThe FAA finds that clarification is necessary. The FAA does not intend that duplicative requirements be included in AD 96-10-11 and this final rule. Therefore, since accomplishment of the modification specified in McDonnell Douglas DC-9 Service Bulletin 53-150 is already required by AD 96-10-11, the FAA has revised paragraph (d) of this final rule to remove that modification requirement from this AD. (The modification requirement was specified in paragraph (f)(2) of the proposed rule.) Additionally, costs associated with accomplishment of that modification have been removed from the cost impact information, below. \n\n\tHowever, accomplishment of the modification described in Revision 3 of McDonnell Douglas Service Bulletin DC9-53-140 is required by AD 96-10-11, whereas this AD requires accomplishment of Revision 05 of that service bulletin. The effectivity listing of Revision 05 of the service bulletin identifies additional airplanes that are subject to the identified unsafe condition. In light of this, the FAA finds that the modification described in that service bulletin must be accomplished on the additional airplanes identified in Revision 05 of the service bulletin, and has revised paragraph (d) of this final rule (paragraph (f)(1) of the proposal) to include that requirement. Further, a note has been added to this final rule to indicate that the modification requirement for airplanes identified in Revision 3 of the service bulletin is specified in AD 96-10-11. \n\n\tIn addition, the final rule has been revised to include a new paragraph (e), which states that accomplishment of the inspection requirements of this AD constitute terminating action for the corresponding inspection requirements of AD 96-10-11. \n\nRequest to Allow DER Approval of Certain Repairs \n\n\tOne commenter requests that the proposed AD be revised to allow approval of repairs not addressed in the cited service bulletins by a McDonnell Douglas Designated Engineering Representative (DER), instead of the Manager of the Los Angeles Aircraft Certification Office (ACO). The commenter states that this provision would result in a more efficient and expeditious repair approval process. \n\n\tThe FAA does not concur. While DER's are authorized to determine whether a design or repair method complies with a specific requirement, they are not currently authorized to make the discretionary determination as to what the applicable requirement is. However, the FAA has issued a notice (N 8110.72, dated March 30, 1998), which provides guidance for delegating authority to certain type certificate holder structural DER's to approve alternative methods of compliance for AD-required repairs and modifications of individual airplanes. The FAA is currently working with Boeing, Douglas Products Division (DPD), to develop the implementation process for delegation of approval of alternative methods of compliance in accordance with that notice. Once this process is implemented, approval authority \nfor alternative methods of compliance can be delegated without revising the 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 569 McDonnell Douglas Model DC-9 series airplanes of the affected design in the worldwide fleet. \n\n\tThe FAA estimates that 403 airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per airplane to accomplish the required inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the inspections on U.S. operators is estimated to be $145,080, or $360 per airplane, per inspection cycle. \n\n\tThe FAA estimates that it will take approximately 174 work hours per airplane to accomplish the required modification of longeron-to-frame attachment area and the frame-to-skin shear clips of the aft fuselage. The cost of required parts will differ, depending on whether the airplane is categorized as a Group 1 airplane or a Group 2 airplane, as defined in the applicable service bulletin. Required parts will cost approximately $13,669 per airplane for Group 1 airplanes, and $10,285 per airplane for Group 2 airplanes. Based on these figures, the cost impact of this modification on U.S. operators is estimated to be $24,109 per airplane for Group 1 airplanes, and $20,725 per airplane for Group 2 airplanes. \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\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: