AD 98-18-22

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -15, and -30 series airplanes, and C-9 (military) airplanes, that requires a one-time visual inspection to determine if all corners of the upper cargo doorjamb have been previously modified; various follow-on repetitive inspections; and modification, if necessary. This amendment is prompted by reports of fatigue cracks found in the fuselage skin and doubler at the corners of the upper 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.

98-18-22 MCDONNELL DOUGLAS: Amendment 39-10738. Docket 96-NM-272-AD. \n\n\tApplicability: Model DC-9-10, -15, and -30 series airplanes, and C-9 (military) airplanes; as listed in McDonnell Douglas Service Bulletin DC9-53-276, dated September 30, 1996; 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 (e) 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 detect and correct fatigue cracking in the fuselage skin or doubler at the corners of the upper 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\tNOTE 3: The words "repair" and "modify/modification" in this AD and the referenced service bulletin are used interchangeably. \n\n\tNOTE 4: This AD will affect principal structural element (PSE) 53.09.023 of the DC-9 Supplemental Inspection Document (SID). \n\n\t(a)\tPrior to the accumulation of 41,000 total landings, or within 3,000 landings after the effective date of this AD, whichever occurs later, perform a one-time visual inspection to determine if the corners of the upper 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 upper cargo doorjamb have not been modified, prior to further flight, perform an x-ray inspection to detect cracks of the fuselage skin and doubler at all corners of the upper cargo doorjamb, in accordance with McDonnell Douglas Service Bulletin DC9-53-276, dated September 30, 1996. \n\n\t\t(1)\tIf no crack is detected during the x-ray inspection required by this paragraph, accomplish the requirements of either paragraph (b)(1)(i) or (b)(1)(ii) of this AD, in accordance with McDonnell Douglas Service Bulletin DC9-53-276, dated September 30, 1996. \n\n\t\t\t(i)\tOption 1. Repeat the x-ray inspection required by paragraph (b) of this AD thereafter at intervals not to exceed 3,000 landings; or \n\n\t\t\t(ii)\tOption 2. Prior to further flight, modify the corner skin of the upper cargo doorjamb, in accordance with the service bulletin. Prior to the accumulation of 28,000landings after accomplishment of the modification, perform an eddy current inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. \n\n\t\t\t\t(A)\tIf no crack is detected on the skin adjacent to the modification during the eddy current inspection required by this paragraph, repeat the eddy current 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 eddy current 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 x-ray inspection required by this paragraph and the crack is 2 inches or less in length: Prior to further flight, modify/repair it in accordance with the service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform an eddy current 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 eddy current inspection required by this paragraph, repeat the eddy current inspection thereafter at intervals not to exceed 20,000 landings.\n\n\t\t\t(ii)\tIf any crack is detected during any eddy current 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 x-ray inspection required by this paragraph and the crack is greater than 2 inches in length: Prior to 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 upper cargo doorjamb have been modified previously: Prior to the accumulation of 28,000 landings after accomplishment of that modification, or within 3,000 landings after the effective date of this AD, whichever occurs later, perform an eddy current inspection to detect cracks on the skin adjacent to the modification, in accordance with McDonnell Douglas Service Bulletin DC9-53-276, dated September 30, 1996. \n\n\t\t(1)\tIf no crack is detected during the eddy current inspection required by this paragraph, repeat the eddy current inspection thereafter at intervals not to exceed 20,000 landings. \n\n\t\t(2)\tIf any crack is detected during any eddy current 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(d)\tAccomplishment of the actions required by this AD constitutes terminating action only for certain requirements of AD 96-13-03, amendment 39-9671 (61 FR 31009, dated June 19, 1996), with respect to PSE 53.09.023, of DC-9 Supplemental Inspection Document (SID) L26-008. \n\n\t(e)\tAnalternative 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 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, Los Angeles ACO. \n\n\t(f)\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(g)\tExcept as provided in paragraphs (a), (b)(1)(ii)(B), (b)(2)(ii), (b)(3), and (c)(2) of this AD, the actions shall be done in accordance with McDonnell Douglas Service Bulletin DC9-53-276, dated September 30, 1996. 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(h)\tThis amendment becomes effective on October 20, 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-9-10, -15, and -30 series airplanes, and C-9 (military) airplanes, was published in the Federal Register on February 26, 1997 (62 FR 8644). That action proposed to require a one-time visual inspection to determine if all corners of the upper cargo doorjamb have been previously modified; various follow-on repetitive inspections; and modification, if necessary. \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\nRequest to Withdraw the Proposed AD \n\n\tOne commenter states that an adequate level of safety is being maintained through the Supplemental Structural Inspection Document (SSID) program and routine maintenance, and that mandating the proposed AD would have an adverse operational impact on all operators. The FAA infers that the commenter does not consider it necessary to issue the proposed AD. \n\n\tThe FAA does not concur. The FAA and the manufacturer have conducted fatigue and damage-tolerance analyses of the upper cargo doorjamb corners. Findings revealed that the fatigue life threshold (Nth) for the doorjamb corners, principal structural element (PSE) 53.09.023, is 41,000 total landings instead of the 82,106 total landings specified in Supplemental Inspection Document (SID) L26-008. In light of these findings, the FAA has determined that neither the SSID program nor routine maintenance is an appropriate means to ensure the detection and correction of such fatigue cracking. The FAA has made no change to the proposed AD. \n\nRequest to Change the Compliance Time for the Inspections \n\n\tOne commenter suggests performing the initial inspection using eddy current at the corners of the upper cargo door jambevery 3,000 cycles. In addition, the commenter suggests performing the x-ray inspection at 9,000 cycles or during a "D" check, whichever comes first. \n\n\tThe FAA does not concur. The FAA does not consider that an eddy current inspection would be appropriate for the initial inspection, as described in the following paragraph. The FAA considers that the following compliance times are appropriate: 3,000 landings (as specified in paragraph (a) of the proposed AD) and prior to further flight (as specified by paragraph (b) of the proposed AD). These inspection intervals were based on the technical factors needed to ensure continued safety of flight. In light of these factors, the FAA has determined that the compliance times required by the proposed AD are necessary, and no change has been made to the final rule. \n\nRequest to Change the Type of Initial Inspection \n\n\tOne commenter suggests performing an eddy current inspection at the corners of the upper cargo door jamb with the door closed instead of the one-time visual inspection required by paragraph (a) of the proposed AD. \n\n\tThe FAA does not concur. The FAA has evaluated findings by the manufacturer which indicate that cracks in the specified area could not be detected by an eddy current inspection while the cargo door is closed. Based on these data, the FAA has determined that the visual inspection required by paragraph (a) of the proposed AD is appropriate. No change has been made to the final rule. \n\nProposed AD Would Have an Adverse Economic Impact \n\n\tThe commenter states that the proposed AD would adversely affect those airlines that use the specified airplanes only for passenger service with the cargo door inoperative. The commenter adds that the economic impact for the visual and x-ray inspections would be approximately $21,500 per airplane per year for a passenger configuration. The FAA infers from these statements that the commenter considers that the inspections required by the proposedNPRM are too expensive. \n\n\tThe FAA does not concur. Because commenter did not provide any substantiating data for its proposed revision to the cost estimate, the FAA considers that the estimate specified by the proposed AD is appropriate. Therefore, the FAA has made no changes to the final rule. \n\nExplanation of Changes Made to the Proposed AD \n\n\tSince issuance of the NPRM, the FAA has added paragraph (d) to the final rule to include a terminating action only for certain requirements of AD 96-13-03, amendment 39-9671 (61 FR 31009, dated June 19, 1996), with respect to PSE 53.09.023, of DC-9 Supplemental Inspection Document (SID) L26-008. \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 final rule with the addition of the change described in the preceding paragraph. The FAA has determined that the final rule will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 93 McDonnell Douglas Model DC-9-10, -15, and -30 series airplanes, and C-9 (military) airplanes of the affected design in the worldwide fleet. The FAA estimates that 80 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 one-time visual inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the one-time visual inspection required by this AD on U.S. operators is estimated to be $4,800, or $60 per airplane. \n\n\tShould an operator be required to accomplish the necessary x-ray inspection, it would 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 any necessary x-ray inspection action is estimated to be $60 per airplane, per inspection cycle.Should an operator be required to accomplish the necessary eddy current inspection, it would 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 any necessary eddy current inspection action is estimated to be $60 per airplane, per inspection cycle. \n\n\tShould an operator be required to accomplish the necessary modification, it would take approximately 14 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. The cost of required parts could range from $714 per airplane to as much as $1,526 per airplane. Based on these figures, the cost impact of any necessary modification action is estimated to be between $1,554 and $2,366 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 ifthis 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 theRules 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\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: