AD 96-11-11

This amendment adopts a new airworthiness directive (AD), applicable to all McDonnell Douglas Model DC-9 series airplanes, that requires inspection(s) to detect cracking in the nose skin of the fuselage, and various follow-on actions. This amendment also provides for an optional modification, which would defer certain repetitive inspections, if no cracking is detected. This amendment is prompted by reports of cracking in the upper nose skin of the fuselage due to fatigue. The actions specified by this AD are intended to prevent fatigue-related cracking, which could compromise the structural integrity of the airplane.

Final rule.

96-11-11 MCDONNELL DOUGLAS: Amendment 39-9636. Docket 95-NM-145-AD. \n\n\tApplicability: All Model DC-9-10, -20, -30, -40, -50, and C-9 (military) series 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 (b)(1) 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 compromise the structural integrity of the airplane, accomplish the following: \n\n\t(a)\tPrior to the accumulation of 40,000 total landings, or within 3,000 landings after the effective date of this AD, whichever occurs later, perform a high frequency eddy current (HFEC) inspection to detect cracking in the nose skin of the fuselage, in accordance with McDonnell Douglas DC-9 Service Bulletin 53-262, dated October 11, 1994. \n\n\t\t(1)\tIf no cracking is detected, accomplish either paragraph (a)(1)(i) or (a)(1)(ii) of this AD, in accordance with the service bulletin. \n\n\t\t\t(i)\tRepeat the HFEC inspection thereafter at intervals not to exceed 4,000 landings; or \n\n\t\t\t(ii)\tAccomplish the modification of the upper nose skin of the cockpit fuselage in accordance with the service bulletin. Prior to the accumulation of 60,000 landings after accomplishment of this modification, perform a visual inspection of the upper nose skinof the cockpit fuselage in accordance with the service bulletin. Repeat the visual inspection thereafter at intervals not to exceed 25,000 landings. \n\n\t\t(2)\tIf any cracking is detected and it is within the repair limits specified in the service bulletin, prior to further flight, repair the cracked nose skin in accordance with the service bulletin. Prior to the accumulation of 60,000 landings after accomplishment of this repair, perform a visual inspection to detect cracking of the repair; and prior to further flight, repair any cracking found during this inspection; in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\t\t(3)\tIf any cracking is detected and it is beyond the repair limits specified in the service bulletin, prior to further flight, repair the cracked nose skin in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(b)\t(1)\tAn alternative method of compliance oradjustment 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(b)\t(2)\tAlternative methods of compliance, approved in accordance with AD 94-03-01, amendment 39-8907, are approved as alternative methods of compliance with paragraphs (a)(2) and (a)(3) of this AD. This approval only applies to repairs that are subject to the requirements of this AD. \n\n\t(c)\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(d)\tThe inspections, modification, and certain repairs shall be done in accordance with McDonnell Douglas DC-9 Service Bulletin 53-262, dated October 11, 1994. 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(e)\tThis amendment becomes effective on July 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 all McDonnell Douglas Model DC-9 series airplanes was published in the Federal Register on January 19, 1996 (61 FR 1301). That action proposed to require inspection(s) to detect cracking in the nose skin of the fuselage, and various follow-on actions. That action also proposed a provision for an optional modification, which would defer certain repetitive inspections, if no cracking is detected. \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 to Extend the Compliance Time \n\n\tOne commenter requests that the "grace period" of the compliance time for the accomplishment of the high frequency eddy current (HFEC) inspection be extended from the proposed 3,000 landings to 4,000 landings. This will allow the HFEC inspection to be accomplished during a regularly scheduled maintenance check, thereby eliminating any additional expenses. In addition, the commenter indicates that it has accomplished the HFEC inspection on 86 Model DC-9 series airplanes and has found "a high rate of positive findings" (i.e., cracking). \n\n\tThe FAA does not concur with the commenter's request to extend the "grace period" of the compliance time. In developing an appropriate compliance time for this action, the FAA considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the HFEC inspection. In consideration of these items, as well as the numerous reports of cracking in the upper nose skin of the fuselage of airplanes in service, the FAA has determined that a "grace period" of 3,000 landings, as proposed, is appropriate. However, under the provisions of paragraph (b) of the final rule, the FAA may approve requests for adjustments to the compliance time if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety. \n\nRequest to Allow DER Approval of Repairs \n\n\tThis commenter also requests that proposed paragraph (a)(3) be revised to permit the approval of repairs (of any cracked areas beyond the repair limits specified in McDonnell Douglas DC-9 Service Bulletin 53-262) by Designated Engineering Representatives (DER) of the McDonnell Douglas Corporation; this will allow a more expeditious response time on repair recommendations. \n\n\tThe FAA does not concur with the commenter's request to revise paragraph (a)(3) of this AD. While DER's are authorized to determine whether a design or repair method complies with a specific requirement, they are not authorized to make the discretionary determination as to what the applicable requirement is. Further, where repair data does not exist, it is essential that the FAA have feedback as to the type of repairs being made. The FAA has determined that the Manager of the Los Angeles Aircraft Certification Office (ACO) should approve any such repairs or other deviations to the AD's requirements. Given that possible new relevant issues might be revealed during this process, it is imperative that the FAA, at this level, have such feedback. Only by reviewing deviation approvals can the FAA be assured of this feedback and of the adequacy of the repair methods. However, the FAA, in conjunction with the Aviation Rulemaking Advisory Committee (ARAC) currently is considering guidelines to address this issue, and may eventually develop additional FAA policy on this subject. \n\nRequest to Allow a Temporary Repair \n\n\tOne commenter requests that the FAA revise the proposal to allow a temporary repair, having a life limit of 8,000 flight cycles, to be accomplished in accordance with Structural Repair Manual 53-04, Figure 12B, Class III, until the proposed permanent repair can be accomplished. This would minimize down time for the operator. \n\n\tThe FAA does not concur. The FAA does not consider it appropriate to include various provisions in an AD applicable to a single operator's unique use of an affected airplane. Paragraph (b) of this AD provides for the approval of alternative methods of compliance to address these types of unique circumstances. \n\nRequest for Clarification of Use of Previously Approved Repairs \n\n\tOne commenter requests clarification as to the use of repairs that have been previously approved by the Manager, Los Angeles ACO, in accordance with AD 94-03-01, amendment 39- 8907 (59 FR 6538, February 11, 1994). \n\n\tThe FAA agrees that clarification is necessary. The FAA considers the subject area of this AD to be identical to the subject area in AD 94-03-01. Therefore, repairs that have been approved previously by the Manager, Los Angeles ACO, are considered to be approved as alternative methods of compliance with paragraphs (a)(2) and (a)(3) of this AD. Accordingly, the FAA has revised the final rule to include a new paragraph (b)(2) to clarify this. \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 change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 889 Model DC-9 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 568 airplanes of U.S. registry will be affected by this AD, that it will take approximately 10 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 $340,800, or $600 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. However, since the issuance of the proposal, the FAA has been advised that the initial inspection required by this AD has been accomplished on at least 86 affected airplanes. Therefore, the future cost impact of this AD on U.S. operators is reduced by approximately $51,600. \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.\tThe 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.\tSection 39.13 is amended by adding the following new airworthiness directive: