AD 99-15-05

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes, that requires a one-time visual inspection to determine if all corners of the aft lower cargo doorjamb have been previously modified. This amendment also requires low frequency eddy current inspections to detect cracks of the fuselage skin and doubler at all corners of the aft lower cargo doorjamb, various follow-on repetitive inspections, and modification, if necessary. This amendment is prompted by fatigue cracks found in the fuselage skin and doubler at the corners of the aft lower cargo doorjamb. The actions specified by this AD are intended to detect and correct such fatigue cracking, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Final rule.

99-15-05 MCDONNELL DOUGLAS: Amendment 39-11224. Docket 97-NM-49-AD.\n\n\tApplicability: Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes, as listed in McDonnell Douglas DC-9 Service Bulletin DC9-53-278, dated November 4, 1996, or McDonnell Douglas DC-9 Service Bulletin DC9-53-278, Revision 01, dated April 29, 1999; 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 thisAD; 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 detect and correct fatigue cracking in the fuselage skin or doubler at the corners of the aft lower cargo doorjamb, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane, accomplish the following:\n\n\tNOTE 2: Where there are differences between the service bulletin and the AD, the AD prevails.\n\n\t(a)\tPrior to the accumulation of 48,000 total landings, or within 3,575 landings after the effective date of this AD, whichever occurs later, perform a one-time visual inspection to determine if the corners of the aft lower cargo doorjamb have been modified prior to the effective date of this AD.\n\n\t(b)\tIf the visual inspection required by paragraph (a) of this AD reveals that the corners of the aft lower cargo doorjamb have not been modified: Prior to further flight, perform a low frequency eddy current (LFEC) or x-ray inspection to detect cracks of the fuselage skin and doubler at all corners of the aft lower cargo doorjamb, in accordance with McDonnell Douglas Service Bulletin DC9-53-278, dated November 4, 1996, or Revision 01, dated April 29, 1999.\n\n\t\t(1)\tIf no crack is detected during the LFEC or x-ray inspection required by this paragraph, accomplish the requirements of either paragraph (b)(1)(i) or (b)(1)(ii) of this AD.\n\n\t\t\t(i)\tOption 1. Repeat the inspections as follows until paragraph (b)(1)(ii) of this AD is accomplished:\n\n\t\t\t\t(A)\tIf the immediately preceding inspection was conducted using LFEC techniques, conduct the next inspection within 3,575 landings.\n\n\t\t\t\t(B)\tIf the immediately preceding inspection was conducted using x-ray techniques, conduct the next inspection within 3,075 landings.\n\n\t\t\t(ii)\tOption 2. Prior to further flight, modify the corners of the aft lower cargo doorjamb, in accordance with either service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of that modification, perform a High Frequency Eddy Current (HFEC) inspection to detect cracks on the skin adjacent to the modification, in accordance with McDonnell Douglas Service Bulletin DC9-53-278, Revision 01, dated April 29, 1999. Repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings.\n\n\t\t\t\t(A)\tIf no crack is detected on the skin adjacent to the modification during any HFEC or x-ray inspection required by paragraph (b) of this AD, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings.\n\n\t\t\t\t(B)\tIf any crack is detected on the skin adjacent to the modification during any HFEC or x-ray inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.\n\n\t\t(2)\tIf any crack is found during any LFEC or x-ray inspection required by paragraph (b) of this AD and the crack is 2 inches or less in length: Prior to further flight, modify it in accordance with McDonnell Douglas Service Bulletin DC9-53-278, Revision 01, dated April 29, 1999. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform an HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin.\n\n\t\t\t(i)\tIf no crack is detected during the HFEC inspection required by this paragraph, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings.\n\n\t\t\t(ii)\tIf any crack is detected during the HFEC inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO.\n\n\t\t(3)\tIf any crack is found during any LFEC or x-ray inspection required by this paragraph and the crack is greater than 2 inches in length: Priorto further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO.\n\n\t(c)\tIf the visual inspection required by paragraph (a) of this AD reveals that the corners of the aft lower cargo doorjamb have been modified, but not in accordance with the DC-9 Structural Repair Manual (SRM) or Service Rework Drawing, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO.\n\n\t(d)\tIf the visual inspection required by paragraph (a) of this AD reveals that the corners of the aft lower cargo doorjamb have been modified in accordance with DC-9 SRM or Service Rework Drawing, prior to the accumulation of 28,000 landings since accomplishment of that modification, or within 3,575 landings after the effective date of this AD, whichever occurs later, perform a HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with McDonnell Douglas Service Bulletin DC9-53-278, Revision 01, dated April 29,1999. Repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings.\n\n\t\t(1)\tIf no crack is detected during any HFEC inspection required by this paragraph, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings.\n\n\t\t(2)\tIf any crack is detected during any HFEC inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO.\n\n\t(e)\tAccomplishment of the actions required by this AD constitutes terminating action for inspections of Principal Structural Element (PSE) 53.09.035 (reference McDonnell Douglas Model DC-9 Supplemental Inspection Document, Report No. L26-008, Section 2 of Volume 1, Revision 5, dated July 1997, as required by AD 96-13-03, amendment 39-9671).\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 CertificationOffice (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)\tExcept as provided in paragraphs (b)(1)(ii)(B), (b)(2)(ii), (b)(3), (c), and (d)(2) of this AD, the actions shall be done in accordance with McDonnell Douglas Service Bulletin DC9-53-278, dated November 4, 1996, and McDonnell Douglas Service Bulletin DC9-53-278, Revision 01, dated April 29, 1999. This incorporation by reference was approved by the Director ofthe 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, P.O. Box 1771, Long Beach, California 90846-1771, Attention: Business Unit Manager, Contract Data Management, C1-255 (35-22). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; 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 August 18, 1999.

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-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes, was published in the Federal Register on August 11, 1997 (62 FR 42949). That action proposed to require a one-time visual inspection to determine if all corners of the aft lower cargo doorjamb have been previously modified. That action also proposed to require low frequency eddy current inspections to detect cracks of the fuselage skin and doubler at all corners of the aft lower cargo doorjamb, various follow-on repetitive inspections, and modification, if necessary.\n\nNew Service Information\n\n\tSince the issuance of the NPRM, McDonnell Douglas has issued Service Bulletin DC9-53-278, Revision 01, dated April 29, 1999. That service bulletin removes reference to a low frequency eddy current inspectionafter doubler installation and changes the inspection to a high frequency eddy current inspection. Other administrative changes were also included in the revised service bulletin.\n\nConsideration of Comments\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\tOne commenter supports the proposal.\n\nRequest to Allow Designated Engineering Representative (DER) Approval of Certain Repairs\n\n\tOne commenter requests that, rather than require approval of Manager of the Los Angeles Aircraft Certification Office (ACO) for certain repairs (cracking conditions beyond the allowable repair limits specified in the proposal, and for existing repairs that are not accomplished in accordance with the DC-9 Structural Repair Manual (SRM) or Service Rework Drawings), a Boeing/Douglas Aircraft Division Designated Engineering Representative (DER) be designated with the authority to approve such repairs temporarily. The commenter states that this would expedite the approval process yet ensure an adequate level of safety since the Manager of the Los Angles ACO would have final authority to approve the repair as a permanent repair. The commenter states that if the FAA does not approve the temporary repair as a permanent repair, it could then require any corrective action to be accomplished, preferably at the next scheduled major maintenance check.\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 andmodifications of individual airplanes. The FAA is currently working with The Boeing Company, Long Beach Division (BLBD), 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 for alternative methods of compliance can be delegated without revising the AD.\n\nRequest to Revise Paragraph (c) of the Proposed AD\n\n\tOne commenter requests that paragraph (c) of the proposed AD be revised to read as follows:\n\n\t"(c)\tIf the visual inspection required by paragraph (a) of this AD reveals that the corners of the aft lower cargo doorjamb have been modified by FAA-approved repairs other than the DC-9 SRM or Service Rework Drawing, prior to further flight, accomplish an initial Low Frequency Eddy Current (LFEC) inspection of the fuselage skin adjacent to the repair.\n\n\t(c)(i)\tIf no cracks are detected, within (6) months after the initial LFEC inspection, accomplisha repair approved by the Manager, Los Angeles ACO.\n\n\t(c)(ii)\tIf cracks are detected, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles ACO."\n\n\tThis commenter states that, as paragraph (c) of the AD is currently worded, it will cause an unnecessary operational impact since FAA-approved non-standard SRM or Service Rework Drawing repairs are known to exist in this area of the doorjamb. The commenter contends that obtaining approval for such repairs from the Los Angeles ACO, prior to further flight, will be time consuming and will result in an unwarranted extended ground time for the airplane.\n\n\tThe FAA does not concur with the commenter's request to revise paragraph (c) of the AD. The FAA, in conjunction with the manufacturer, has conducted further analysis of this issue. The FAA has determined that, for cargo doorjambs that are found to be modified previously, but not in accordance with the DC-9 SRM or Service Rework Drawing, an initial LFEC inspection of the fuselage skin adjacent to those existing repairs, as suggested by the commenter, will not detect any cracking under the repairs. The FAA considers that, once cracking emerges from under a repair, crack growth could rapidly occur. In light of these findings, no change to the final rule is necessary.\n\nRequest to Revise DC-9 Supplemental Inspection Document (SID)\n\n\tOne commenter requests that, prior to issuance of the final rule, the DC-9 SID be revised to incorporate the actions required by this AD. The commenter states that such a revision will eliminate confusion between the DC-9 SID and the AD. The FAA does not concur. The actions required by this AD are necessary to detect and correct the identified unsafe condition. After issuance of the final rule, the manufacturer may revise the DC-9 SID.\n\nOther Relevant Rulemaking\n\n\tThe FAA has revised the final rule to include a new paragraph (e). This new paragraph states that accomplishment of the inspection requirements of this AD constitutes terminating action for inspections of Principal Structural Element (PSE) 53.09.035 (reference McDonnell Douglas Model DC-9 Supplemental Inspection Document, Report No. L26-008, Section 2 of Volume 1, Revision 5, dated July 1997, as required by AD 96-13-03, amendment 39-9671 (61 FR 31009, June 19, 1996)). Since this new paragraph is being added, "NOTE 3" of the proposal, which discussed the relation of this AD to AD 96-13-03 is no longer necessary. Therefore, the FAA has removed "NOTE 3" of the proposal and renumbered the NOTES in the final rule accordingly.\n\nOther Changes to the Final Rule\n\n\tBased on new information received from the manufacturer, the FAA has revised the cost estimate for parts that would be needed if an operator were to find it necessary to accomplish the modification specified in this final rule. The Cost Impact section of the NPRM stated that the estimated cost for those parts would be $692 to $990 per airplane. The revised figure for the estimated parts cost is $936 to $2007 per airplane. The final rule has been revised accordingly.\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 899 McDonnell Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes of the affected design in the worldwide fleet. The FAA estimates that 622 airplanes of U.S. registry will be affected by this AD.\n\n\tIt will take approximately 1 work hour per airplane to accomplish the required visual inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the visual inspection required by this ADon U.S. operators is estimated to be $37,320, or $60 per airplane.\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\n\tShould an operator be required to accomplish the eddy current inspections, it will take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the eddy current inspections required by this AD on U.S. operators is estimated to be $37,320, or $60 per airplane.\n\n\tShould an operator be required to accomplish the modification, it will take approximately 14 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $936 or $2,807 per airplane, depending on the service kit purchased. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $1,776 or $3,647 per airplane.\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\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.\n\nAdoption of the Amendment\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\t1. The authority citation for part 39 continues to read as follows:\nAuthority: 49 U.S.C. 106(g), 40113, 44701.\n\n§ 39.13 (Amended)\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: