AD 98-26-09

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 the doorstops and corners of the doorjamb of the forward passenger door have been 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 and doorstops of the doorjamb of the forward passenger 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.

98-26-09 MCDONNELL DOUGLAS: Amendment 39-10949. Docket 98-NM-06-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 DC9-53-280, Revision 01, dated July 30, 1998; 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 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 doorstops and corners of the doorjamb of the forward passenger 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 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 doorstops and corners of the forward passenger door doorjamb have been modified. Perform the inspection in accordance with McDonnell Douglas Service Bulletin DC9-53-280, dated December 1, 1997, or Revision 01, dated July 30, 1998, \n\n\t(b)\tFor airplanes identified as Group 1 in McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998: If the visual inspection required by paragraph (a) of this AD reveals that the doorstops and corners of the forward passenger door doorjamb have not been modified, prior to further flight, perform a low frequency eddy current (LFEC) or x-ray inspection to detect cracks at all corners and doorstops of the forward passenger door doorjamb, in accordance with McDonnell Douglas Service Bulletin DC9-53-280, dated December 1, 1997, or Revision 01, dated July 30, 1998. \n\n\t\t(1)\tGroup 1, Condition 1. If no crack is detected during any LFEC or x-ray inspection required by paragraph (b) of this AD, accomplish the requirements of either paragraph (b)(1)(i) or (b)(1)(ii) of this AD, in accordance with the service bulletin. \n\n\t\t\t(i)\tOption 1. Repeat the LFEC inspection required by this paragraph thereafter at intervalsnot to exceed 3,575 landings, or the x-ray inspection required by this paragraph thereafter at intervals not to exceed 3,075 landings; or \n\n\t\t\t(ii)\tOption 2. Prior to further flight, modify the doorstops and corners of the forward passenger door doorjamb, in accordance with the service bulletin. 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. \n\n\t\t\t\t(A)\tIf no crack is detected on the skin adjacent to the modification during any HFEC inspection required by paragraph (b)(1)(ii) 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 inspection required by paragraph (b)(1)(ii) of this AD, prior to further flight, repair it in accordance with a method approved bythe Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\t\t(2)\tGroup 1, Condition 2. If any crack is found during any LFEC or x-ray inspection required by paragraph (b) of this AD, and the crack is 0.50 inch or less in length: Prior to further flight, modify the doorstops and corners of the forward passenger door doorjamb 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.\n\n\t\t\t(i)\tIf no crack is detected on the skin adjacent to the modification during any HFEC inspection required by paragraph (b)(2) of this AD, repeat the HFEC 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 HFEC inspection required by paragraph (b)(2) of this AD, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t\t(3)\tGroup 1, Condition 3. If any crack is found during any LFEC or x-ray inspection required by paragraph (b) of this AD, and the crack is greater than 0.5 inch 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. For airplanes identified as Group 2 in McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998: If the visual inspection required by paragraph (a) of this AD reveals that the doorstops and corners of the forward passenger door doorjamb have been modified previously in accordance with the McDonnell Douglas 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 DC9-53-280, dated December 1, 1997, or Revision 01, dated July 30, 1998.(1)\tOption 1. Prior to the accumulation of 28,000 landings after accomplishment of the modification, or within 3,500 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 the service bulletin. \n\n\t\t\t(i)\tIf no crack is detected on the skin adjacent to the modification during any HFEC inspection required by paragraph (c)(1) of this AD, repeat the HFEC 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 HFEC inspection required by paragraph (c)(1) of this AD, prior to further flight, 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 doorstops and corners of the forward passenger door doorjamb in accordance with the service bulletin. Prior to the accumulation of 28,000 landings after the accomplishment of the modification, perform a 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 on the skin adjacent to the modification during any HFEC inspection required by paragraph (c)(2) of this AD, repeat the HFEC 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 HFEC inspection required by paragraph (c)(2) of this AD, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(d)\tGroup 2, Condition 2. For airplanes identified as Group 2 in McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998: If the visual inspection required by paragraph (a) of this AD reveals that the doorstops and corners of the forward passenger door doorjamb have been modified previously in accordance with McDonnell Douglas DC-9 SRM or Service Rework Drawing, using an aluminum doubler, prior to the accumulation of 28,000 landings after the accomplishment of the modification, or within 3,500 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 DC9-53-280, dated December 1, 1997, or Revision 01, dated July 30, 1998. \n\n\t\t(1)\tIf no crack is detected on the skin adjacent to the modification during any HFEC inspection required by paragraph (d) of this AD, repeat the HFEC 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 HFEC inspection required by paragraph (d) of this AD, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(e)\tGroup 2, Condition 3. For airplanes identified as Group 2 in McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998: If the visual inspection required by paragraph (a) of this AD reveals that the doorstops and corners of the forward passenger door doorjamb have been modified previously, but not in accordance with McDonnell Douglas DC9 SRM or the 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) 53.09.031 (reference McDonnell Douglas Model DC-9 Supplemental Inspection Document) required by AD 96-13-03, amendment 39-9671. \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 ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who mayadd 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 by paragraphs (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 DC9-53-280, dated December 1, 1997; or McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998. 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, Dept. 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(j)\tThis amendment becomes effective on January 22, 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 April 20, 1998 (63 FR 19423). That action proposed to require a one-time visual inspection to determine if the doorstops and corners of the doorjamb of the forward passenger door have been modified, various follow-on repetitive inspections, and modification, if necessary. \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 proposed rule. Request to Withdraw Proposed Rule One commenter states that, while it has found cracking in the area of the forward passenger door doorjamb over the past 15 years, findings have tapered off. The commenter has found cracking through its FAA-approved maintenance program, and continues to monitor the area through that program. The commenter has not found a crack in the area adjacent to a modified doorjamb. The area is not hidden and is presently inspected at each "C" check. The commenter believes the forward passenger door doorjamb is being maintained at a safe level without the need of "an AD note." \n\n\tThe FAA infers from these remarks that the commenter requests the proposed rule be withdrawn. The FAA does not concur. Based on fatigue and damage tolerance analyses of cracked forward passenger door doorjambs conducted by the manufacturer, the FAA finds that issuance of this final rule is necessary to ensure an adequate level of safety for the affected fleet. \n\nRequest to Extend Compliance Time \n\n\tThe same commenter requests that the FAA extend the proposed compliance time for inspections of previously modified doorjams from 3,000to 3,500 landings. The commenter indicates that this increase would help bridge the inspection requirements into its maintenance program. The commenter states that an added 500 landings will not cause the condition of the doorjamb to develop into an unsafe condition with the doorjamb modified previously. The commenter adds that since the proposed grace period for the initial (one-time visual) inspection is 3,575 landings, the compliance time for inspections of modified doorjambs should not be any different. \n\n\tThe FAA concurs with the commenter's request. Following careful consideration of this comment, and in light of the commenter's statement that no cracking has been found in the area adjacent to a modified doorjamb during "C" check inspections, the FAA considers that an extension of the repetitive inspection interval to 3,500 landings will not compromise safety. Paragraphs (c)(1) and (d) of this final rule have been revised accordingly. \n\nRequest to Revise Inspection Intervals \n\n\tAnother commenter requests that the proposed initial inspection intervals be changed to correspond with those presently in the DC-9 Supplemental Inspection Document (SID) program - that is, initial inspections should be required within a 3-year interval after the effective date of the AD or prior to the accumulation of 48,000 total landings, whichever occurs later, and repetitive intervals should remain at 3,575 landings. \n\n\tThe FAA does not concur. The FAA has determined that cracking of the forward passenger door doorjamb is fatigue related. The initial and repetitive inspection intervals were calculated based on fatigue and damage tolerance analyses. The FAA considers that revising the compliance time as suggested by the commenter will not address the identified unsafe condition in a timely manner. \n\nRequest to Revise DC-9 SID Program \n\n\tOne commenter requests that, prior to issuance of the final rule, the DC-9 SID program be revised to eliminate the inspection requirements of the SID in the area addressed by this proposed AD. The commenter states that such revision will eliminate confusion between the SID program and this proposed AD. \n\n\tThe FAA does not concur that the SID program should be revised prior to issuance of this final rule. The actions required by this AD area necessary to detect and correct the identified unsafe condition. Following issuance of the final rule, the manufacturer may revise the DC-9 SID program. However, to eliminate any confusion between this AD and the SID program, the FAA has added a new paragraph (f) to this final rule to specify that accomplishment of the actions required by this AD constitutes terminating action for the requirements of AD 96-13-03, amendment 39-9671 (61 FR 31009, June 19, 1996), for the affected PSE. Since this new paragraph is being added, the FAA has removed "NOTE 4" of the proposed AD since it is no longer necessary. \n\nRequest to Revise Paragraph (e) of the Proposed Rule \n\n\tOne commenter requests that paragraph (e) of the proposed rule be revised to require that, if the visual inspection required by paragraph (a) of the AD reveals that the doorstops and corners of the forward passenger door doorjamb have been modified previously in accordance with FAA-approved repairs other than those specified in the DC-9 Structural Repair Manual (SRM) or Service Rework Drawing, prior to further flight, an initial low frequency eddy current (LFEC) inspection of the fuselage skin adjacent to the repair should be accomplished. If no cracks are detected, repair should be required within 6 months; if any crack is detected, repair should be required prior to further flight. (As proposed, paragraph (e) requires that operators repair, prior to further flight, in accordance with a method approved by the FAA if the visual inspection required by paragraph (a) of the AD reveals that the doorstops and corners of the forward passenger door doorjamb have been modified previously, but notin accordance with the McDonnell Douglas DC-9 SRM or the Service Rework Drawing.) The commenter states that, as proposed, the requirement will cause an unnecessary operational impact since FAA-approved, non-standard SRM repairs are known to exist in this area of the doorstops and corners. The commenter indicates that obtaining approval for such repairs prior to further flight will be time consuming and will result in an unwarranted, extended groundtime for affected airplanes. The commenter believes that its recommendation will ensure that an equivalent level of safety is maintained while minimizing the operational impact to operators. The commenter adds that this will allow ample time to document and submit the repair to the manufacturer for a damage tolerance review and subsequent approval by the FAA. \n\n\tThe FAA does not concur with the commenter's request. The FAA, in conjunction with the manufacturer, has conducted further analysis concerning this issue. The FAA has determined that previous repairs of the forward passenger door doorjamb that were not accomplished in accordance with the DC-9 SRM or Service Rework Drawing, or that were not approved by the FAA, are not considered to be FAA-approved repairs; accomplishment of the initial LFEC inspection of the fuselage skin adjacent to those existing repairs would not detect any crack 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. Therefore, any doorjambs that were modified previously in accordance with non-FAA-approved repairs must be repaired prior to further flight in accordance with a method approved by the FAA. \n\nRequest to Revise Cost Impact Information \n\n\tOne commenter states that the FAA has underestimated the cost impact of the proposed AD. The commenter indicates that the proposed low frequency eddy current or high frequency eddy current inspection will require a minimum of 4 work hours per airplane for setup, accomplishment, and teardown. Additionally, the commenter believes that the full modification will require approximately 500 to 600 work hours per airplane. \n\n\tThe FAA concurs partially. The manufacturer has advised the FAA that the modification will require approximately 30 work hours, as estimated in the proposed AD. No change to the final rule has been made in this regard. However, the manufacturer indicates that the eddy current inspection will require approximately 1.5 work hours per airplane. In light of this information, the FAA has revised the cost impact information, below, to specify that approximately 2 work hours per airplane will be required to accomplish the inspection, as necessary. \n\nChange to Service Bulletin Citation \n\n\tSince the issuance of the proposed rule, the FAA has reviewed and approved McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998. This revision of the service bulletin is essentially identical to the original issue, which was cited in the proposed AD as the appropriate source of service information for accomplishment of the actions specified in the AD. Revision 01 simply deletes from the effectivity of the service bulletin Model MD-80 series airplanes that are not affected. This revision also changes the lead time for availability of kits to 150 days. This final rule has been revised to include Revision 01 of the service bulletin as an additional source of service information. \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 ImpactThere are approximately 1,001 airplanes of the affected design in the worldwide fleet. The FAA estimates that 656 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 visual inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the visual inspection of this AD on U.S. operators is estimated to be $39,360, or $60 per airplane. \n\n\tShould an operator be required to accomplish the 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 any necessary LFEC or x-ray inspection specified in 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 HFEC inspection, it will take approximately 2 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of any necessary HFEC inspection specified in this AD on U.S. operators is estimated to be $120 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 between $490 and $1,775 per airplane, depending on the service kit purchased. Based on these figures, the cost impact of any necessary modification specified in this AD on U.S. operators is estimated to be between $2,290 and $3,575 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\nRegulatory Impact \n\n\tThe regulations adopted herein will not havesubstantial 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 thecaption "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. \t 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: