AD 98-26-08

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 doorjamb of the forward service door have been previously modified. The action also requires various repetitive inspections to detect cracks of the fuselage skin and doubler at all corners of the doorjamb of the forward service door, and to detect cracks on the skin adjacent to the modification; and various follow-on actions. This amendment is prompted by reports of fatigue cracks found in the fuselage skin and doubler at the corners of the doorjamb of the forward service door. 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.

98-26-08 MCDONNELL DOUGLAS: Amendment 39-10948. Docket 97-NM-56-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 Service Bulletin DC9-53-279, Revision 01, dated May 6, 1997; 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 (g) 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 includespecific 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 doorjamb of the forward service door, 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\t(a)\tPrior to the accumulation of 50,000 total landings, or within 3,225 landings after the effective date of this AD, whichever occurs later, perform a one-time visual inspection to determine if the corners of the doorjamb of the forward service door have been modified prior to the effective date of this AD. \n\n\t(b)\tGroup 1. If the visual inspection required by paragraph (a) of this AD reveals that the corners of the doorjamb of the forward service door 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 doorjamb of the forward service door, in accordance with McDonnell Douglas Service Bulletin DC9-53-279, dated December 10, 1996, or Revision 01, dated May 6, 1996. \n\n\t\t(1)\tCondition 1. If no crack is detected during any inspection required by paragraph (b) of this AD, accomplish 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 3,225 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 doorjamb of the forward service door in accordance with the service bulletin; this modification constitutes terminating action for the repetitive inspection requirements of paragraph (b)(1)(i) of this AD. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform a high frequency eddy current (HFEC) inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. Within 20,000 landings after accomplishment of the HFEC inspection, perform an eddy current inspection to detect cracks in the subject area, 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 any eddy current inspection required by paragraph (b)(1)(ii) of this AD, 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 paragraph (b)(1)(ii) of this AD, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t\t(2)\tCondition 2. If any crack is found during any 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 the service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform a HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. Within 20,000 landings after accomplishment of the HFEC inspection, perform an eddy current inspection to detect cracks in the subject area, in accordance with the service bulletin. \n\n\t\t\t(i)\tIf no crack is detected on the skin adjacent to the modification during any eddy current inspection required by paragraph (b)(2) of this AD, 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 on the skin adjacent to the modification during any eddy current inspection required by paragraph (b)(2) of this AD, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t\t(3)\tCondition 3. If any crack is found during any 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)\tGroup 2, Condition 1. If the visual inspection required by paragraph (a) of this AD reveals that the corners of the doorjamb of the forward service door have been modified in accordance with the DC-9 Structural Repair Manual (SRM) (using a steel doubler), accomplish either paragraph (c)(1) or (c)(2) of this AD in accordance with McDonnell Douglas Service Bulletin DC9-53-279, dated December 10, 1996, or Revision 01, dated May 6, 1997.(1)\tOption 1. Prior to the accumulation of 6,000 landings after the effective date of this AD, perform a HFEC inspection to detect cracks on the skin adjacent to the modification in accordance with the service bulletin. Within 3,000 landings after accomplishment of the HFEC inspection, perform an eddy current inspection to detect cracks in the subject area, in accordance with the service bulletin. \n\n\t\t\t(i)\tIf no crack is detected on the skin adjacent to the modification during any eddy current inspection required by paragraph (c)(1) of this AD, repeat the eddy current inspection thereafter at intervals not to exceed 3,000 landings. \n\n\t\t\t(ii)\tIf any crack is detected on the skin adjacent to the modification during any eddy current inspection required by paragraph (c)(1) of this AD, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t\t(2)\tOption 2. Prior to further flight, modify the corners of the doorjamb of the forward service door in accordancewith the service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform a HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. Within 20,000 landings after accomplishment of the HFEC inspection, perform an eddy current inspection to detect cracks in the subject area, in accordance with the service bulletin. \n\n\t\t\t(i)\tIf no crack is detected on the skin adjacent to the modification during any eddy current inspection required by paragraph (c)(2) of this AD, 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 on the skin adjacent to the modification during any eddy current inspection required by paragraph (c)(2) of this AD, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(d)\tGroup 2, Condition 2. If the visual inspection required by paragraph (a) of this AD reveals that the corners of the doorjamb of the forward service door have been modified in accordance with DC-9 SRM or Service Rework Drawing (using an aluminum doubler), prior to the accumulation of 28,000 landings since accomplishment of the modification, or within 3,225 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 DC9-53-279, dated December 10, 1996, or Revision 01, dated May 6, 1997. Within 20,000 landings after accomplishment of the HFEC inspection, perform an eddy current inspection to detect cracks in the subject area, in accordance with the service bulletin. \n\n\t\t(1)\tIf no crack is detected on the skin adjacent to the modification during any eddy current inspection required by paragraph (d) of this AD, repeat the eddy current inspection thereafter at intervals not to exceed 20,000 landings. \n\n\t\t(2)\tIf any crack is detected on the skin adjacent to the modification during any eddy current inspection required by paragraph (d) of this AD, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(e)\tGroup 2, Condition 3. If the visual inspection required by paragraph (a) of this AD reveals that the corners of the doorjamb of the forward service door have been modified, but not in accordance with the DC-9 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(f)\tAccomplishment of the actions required by this AD constitutes terminating action for inspections of Principal Structural Element (PSE) 53.09.033 (reference McDonnell Douglas Model DC-9 Supplemental Inspection Document) required by AD 96-13-03, amendment 39-9671 (61 FR 31009). \n\n\t(g)\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 4: 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(h)\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(i)\tExcept as provided in paragraphs (a), (b)(1)(ii)(B), (b)(2)(ii), (b)(3), (c)(1)(ii), (c)(2)(ii), (d)(2), and (e) of this AD, the actions shall be done in accordance with McDonnell Douglas Service Bulletin DC9-53-279, dated December 10, 1996, and Revision 01, dated May 6, 1997. 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, 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(j)\tThis amendment becomes effective on January 26, 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 12, 1997 (62 FR 43128). That action proposed to require a one-time visual inspection to determine if all corners of the doorjamb of the forward service door have been previously modified. The action also proposed to require various repetitive inspections to detect cracks of the fuselage skin and doubler at all corners of the doorjamb of the forward service door, and to detect cracks on the skin adjacent to the modification; 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\nRequest to Allow Designated Engineering Representative (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), that 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. TheFAA is currently working with Boeing, 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 Requirements of Proposed AD \n\n\tOne commenter requests that paragraph (e) of the proposed AD be revised to read as follows: \n\n\t"(e)\tIf the visual inspection required by paragraph (a) of this AD reveals that the corners of the forward service door doorjamb have been modified by FAA-approved repairs other than those specified by the DC-9 Structural Repair Manual (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(e)\t(i)\tIf no crack is detected, within (6) months after the initial LFEC inspection, repair in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(e)\t(ii)\tIf any crack is 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 (e) of the proposed 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 (e) of the AD. The FAA in conjunction with McDonnell Douglas has conducted further analysis of this issue. The FAA has determined that, for forward service door doorjambs that are found to be modified previously but not in accordance with the DC-9SRM or Service Rework Drawing, an initial LFEC inspection of the fuselage skin adjacent to those existing repairs will not detect any cracking under the repairs. Because cracking under the repairs could grow rapidly once it emerges from under the repairs, the FAA does not consider that an acceptable level of safety can be assured simply by determining that cracking has not yet emerged from under the repairs. In light of these findings, no change to the final rule is necessary. \n\nRequest to Increase Repetitive Inspection Interval \n\n\tOne commenter requests that the repetitive inspection interval specified by paragraph (b)(1)(i)(A) of the proposed AD be increased from 3,225 landings to 3,575 landings. The commenter states that such an increase of the inspection interval would allow affected airplanes to be inspected during major scheduled maintenance checks, and would reduce the number of line airplanes that would be taken out of service as a result of any findings during the inspection. \n\n\tThe FAA does not concur that the repetitive inspection interval should be increased. The operator provided no technical justification for revising the repetitive inspection interval as requested. Fatigue cracking of the fuselage skin and doubler at the corners of the doorjamb of the forward service door is an identified safety issue, and the FAA has determined that the repetitive inspection interval, as proposed, is warranted, based on the effectiveness of the inspection procedure to detect cracking. The FAA considered not only those safety issues in developing an appropriate repetitive inspection interval for this action, but the recommendations of the manufacturer and the practical aspect of accomplishing the required inspection within an interval of time that parallels normal scheduled maintenance for the majority of affected operators. In light of these factors, the FAA has determined that the inspection interval of 3,225 landings, as proposed, is appropriate. Request 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\nExplanation of Changes Made to the Final Rule \n\n\tThe FAA has revised the final rule to include a new paragraph (f). This new paragraph states that accomplishment of the inspection requirements of this AD constitutes terminating action for inspections of Principal Structural Element (PSE) 53.09.033 (reference McDonnell Douglas Model DC-9 Supplemental Inspection Document) required by AD 96-13-03, amendment 39-9671 (61 FR 31009, June 19, 1996). Since this new paragraph is being added, the FAA has removed "NOTE 4," which is no longer necessary. \n\n\tThe FAA notes that an editorial change is necessary to clarify the intent of paragraph (b) of the proposed rule. The first sentence in that paragraph refers to the corners of the "upper cargo doorjamb." The intent of that sentence is to determine if the visual inspection reveals that the corners of the doorjamb of the forward service door have not been modified, not the "upper cargo doorjamb." The FAA has revised the final rule to specify this clarification. \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 823 McDonnell Douglas 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 575 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 AD on U.S. operators is estimated to be $34,500, or $60 per airplane. \n\n\tShould an operator be required to accomplish the HFEC, LFEC, or x-ray inspection, 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 inspection required by this AD on U.S. operators is estimated to be $60 per airplane, per inspection cycle. \n\n\tShould an operator be required to accomplish the modification, it will take approximately 30 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,256, $1,420, $5,804, or $6,113 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 $3,056, $3,220, $7,604, or $7,913 per airplane, respectively. \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, \nFebruary 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: Authority: 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: