AD 2002-04-01

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 series airplanes; Model MD-88 airplanes; and Model MD-90 airplanes, that currently requires a visual check to determine the part and serial numbers of the upper lock link assembly of the nose landing gear (NLG); repetitive inspections of certain upper lock link assemblies to detect fatigue cracking; and modification of the NLG. The existing AD also provides for terminating action for the repetitive inspections. This amendment requires, among other actions, expanding the applicability of the existing AD, revising compliance times; and adding new inspection requirements. This amendment is prompted by a report indicating that an NLG upper lock link fractured prior to landing and jammed against the NLG shock strut, restricting the NLG from fully extending. The actions specified by this AD are intended to prevent the upper lock link assembly fromfracturing due to fatigue cracking, and the NLG consequently failing to extend fully; this condition could result in injury to passengers and flight crew, and damage to the airplane.

Final rule.

2002-04-01 McDonnell Douglas: Amendment 39-12658. Docket 97-NM-298-AD. Supersedes AD 97-02-10, Amendment 39-9895. \n\n\tApplicability: Model DC-9, DC-9-80, and C-9 series airplanes; Model MD-88 airplanes; and Model MD-90 airplanes; as listed in Boeing Service Bulletins DC9-32-315, and MD90-32-033, both Revision 01, dated October 24, 2000; certificated in any category; equipped with upper lock links, part number (P/N) 3914464-1, -501, or -503. \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)(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 the upper lock link assembly of the nose landing gear (NLG) from fracturing due to fatigue cracking, and the NLG consequently failing to extend fully, which could result in injury to passengers and flight crew, and damage to the airplane, accomplish the following: \n\nRemoving and Retaining Upper Lock Link \n\n\t(a) Remove and retain the upper lock link, P/N 3914464-1, -501, or -503, and attaching parts; and do the inspections required by paragraphs (b) and (c) of this AD, per either applicable Boeing and McDonnell Douglas service bulletins listed in Table 1 of this AD. The actions required by this paragraph shall be done at the applicable time specified in paragraph (a)(1) or (a)(2) of this AD. Table 1 is as follows: \n\nTable 1\n\nModel\nService bulletin\nRevision level\nDate \nDC-9, DC-9-80, and C-9 series airplanes; and MD-88 airplanes. \nMcDonnell Douglas Service Bulletin DC9-32-315. \nOriginal\nMarch 11, 1999. \n\nBoeing Service Bulletin DC9-32-315.\nRevision 01\nOctober 24, 2000.\nMD-90 airplanes\nMcDonnell Douglas Service Bulletin MD90-32-033. \nOriginal\nMarch 11, 1999. \n\nBoeing Service Bulletin MD90-32-033.\nRevision 01\nOctober 24, 2000. \n\n\t\t(1) For airplanes on which the inspection required by paragraph (c)(1) of AD 97-02-10 has been done: Do the actions before 5,000 landings since the last inspection done per paragraph (c)(1) of AD 97-02-10, or within 90 days after the effective date of this AD, whichever occurs later. \n\n\t\t(2) For airplanes on which the inspection required by paragraph (c)(1) of AD 97-02-10 has NOT been done: Do the actions within 2,500 landings on the NLG upper lock link after the effective date of this AD. \n\nInspection \n\n\t(b) Do a one-time inspection ofthe NLG upper lock link assembly per Revision 01 of the applicable service bulletin listed in Table 1 of this AD to determine whether the serial number of the lock link is identified in the affected lot specified in Condition 1 of the Accomplishment Instructions of Revision 01 of the applicable Boeing and McDonnell Douglas service bulletins listed in Table 1 of this AD. \n\nCondition 1 (Hand Forging Serial Number) \n\n\t\t(1) If the serial number of the upper lock link is not from the affected lot specified in Revision 01 of the applicable service bulletin (Condition 1), before further flight, do the etch inspection required by paragraph (c) of this AD. \n\n\t\t(2) If the serial number of the upper lock link is from the affected lot specified in the Revision 01 of the applicable service bulletin (Condition 1), before further flight, replace the lock link with a new upper lock link, P/N 3914464-507; a reidentified upper lock link by adding an "F" to the part number, using an electro chemical deep etch method; or a new upper lock link assembly, P/N 5965065-507; all made from die forged aluminum material; per the applicable service bulletin. Accomplishment of the replacement constitutes terminating action for the requirements of this AD. \n\nEtch Inspection \n\n\t(c) Perform a one-time etch inspection of the NLG upper lock link to determine whether the lock link is made from die forged aluminum material (Condition 2), or from plate or bar material (Condition 3); per the applicable Boeing and McDonnell Douglas service bulletins listed in Table 1 of this AD. \n\nCondition 2 (Die Forged Aluminum Material) \n\n\t\t(1) If the upper lock link is made from die forged aluminum material, before further flight, restore the finish and reidentify the lock link by adding an "F" to the part number, using an electro chemical deep etch method, per the applicable service bulletin. Identification of the lock link as being made from die forged aluminum material constitutes terminating action for the requirements of this AD. \n\nCondition 3 (Plate or Bar Material) \n\n\t\t(2) If the NLG upper lock link is made from plate or bar material, before further flight, do either Condition 3, Option 1, as specified by paragraph (c)(2)(i) of this AD, or Condition 3, Option 2, as specified by paragraphs (c)(2)(ii) and (c)(2)(iii) of this AD. \n\nCondition 3, Option 1 \n\n\t\t\t(i) Permanently remove any discrepant upper lock link and replace with a new upper lock link, P/N 3914464-507; a reidentified upper lock link by adding an "F" to the part number, using an electro chemical deep etch method; or a new upper lock link assembly, P/N 5965065-507; all made from die forged aluminum material; per the applicable service bulletin. Accomplishment of the replacement constitutes terminating action for the requirements of this AD. \n\nCondition 3, Option 2 \n\n\t\t\t(ii) Restore the link finish and reidentify the upper lock link by adding a black paint stripe adjacent to the part number, indicating thatthe part is not made from die forged aluminum material, per the applicable service bulletin. \n\n\t\t\t(iii) Do a high frequency eddy current (HFEC) or Type I fluorescent penetrant inspection of the upper lock link assembly, P/N 3914464-1, -501, or -503, to detect cracking of the assembly; per McDonnell Douglas Alert Service Bulletin DC9-32A298 R02, Revision 02 (for Model DC-9, DC-9-80, and C-9 series airplanes; and Model MD-88 airplanes), or Alert Service Bulletin MD90-32A019 R02, Revision 02 (for Model MD-90 airplanes), both dated October 29, 1997; as applicable. \n\nActions Following the Inspection Required by Paragraph (c)(2)(iii) of This AD \n\n\t(d) If no crack is detected during the HFEC or Type I fluorescent penetrant inspection required by paragraph (c)(2)(iii) of this AD, within 2,500 landings on the NLG upper lock link since accomplishment of the inspection performed per paragraph (c)(2)(iii) of this AD, as applicable, do that inspection a second time. If no crack is detected during this second inspection, within 2,500 landings after accomplishment of the second inspection, replace the upper lock link with a new upper lock link, P/N 3914464-507; a reidentified upper lock link by adding an "F" to the part number, using an electro chemical deep etch method; or a new upper lock link assembly, P/N 5965065-507; all made from die forged aluminum material; per the applicable Boeing and McDonnell Douglas service bulletins listed in Table 1 of this AD. Accomplishment of the replacement action constitutes terminating action for the requirements of this AD. \n\n\t(e) If any crack is detected during the HFEC or Type I fluorescent penetrant inspection required by paragraph (c)(2)(iii) or (d) of this AD, before further flight, replace the discrepant NLG upper lock link with a new upper lock link, P/N 3914464-507; a reidentified upper lock link by adding an "F" to the part number, using an electro chemical deep etch method; or a new upper lock link assembly, P/N 5965065-507; all made from die forged aluminum material; per the applicable Boeing and McDonnell Douglas service bulletins listed in Table 1 of this AD. Accomplishment of the replacement constitutes terminating action for the requirements of this AD. \n\nAlternative Methods of Compliance \n\n\t(f)(1) An 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. 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\t(2) Alternative methods of compliance, approved previously in accordance with AD 97-02-10, amendment 39-9895, are approved as alternative methods of compliance withthis AD. \n\nSpecial Flight Permits \n\n\n\t(g) Special flight permits may be issued in accordance with Secs. 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\nIncorporation by Reference \n\n\t(h)(1) The actions shall be done per the applicable Boeing service bulletin listed in Table 2 of this AD. Table 2 is as follows: \n\nTable 2\n\nService bulletin\nRevision level\nDate \n(i) McDonnell Douglas Service Bulletin DC9-32-315\nOriginal\nMarch 11, 1999. \n(ii) Boeing Service Bulletin DC9-32-315\n01\nOctober 24, 2000. \n(iii) McDonnell Douglas Service Bulletin MD90-32-033\nOriginal\nMarch 11, 1999. \n(iv) Boeing Service Bulletin MD90-32-033\n01\nOctober 24, 2000. \n(v) McDonnell Douglas Alert Service Bulletin DC9-32A298 R02\n02\nOctober 29, 1997. \n(vi) McDonnell Douglas Alert Service Bulletin MD90-32A019 R02\n02\nOctober 29, 1997. \n\n\t\t(2) 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 Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). 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, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(i) This amendment becomes effective on March 28, 2002.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 97-02-10, amendment 39-9895 (62 FR 3781, January 27, 1997), applicable to certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 series airplanes; Model MD-88 airplanes; and Model MD-90 airplanes, was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on February 14, 2001 (66 FR 10243). That supplemental NPRM would have, among other actions, revised a list of suspect parts; delayed accomplishment of a certain replacement; and revised the initial compliance time proposed by the original NPRM. \n\nComments \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 for Credit for Previously Accomplished Actions \n\n\tOne commenter requests that the FAA revise the proposed AD to specify that operators will be given "credit" for having previously accomplished the actions required by AD 97-02-10 per McDonnell Douglas Service Bulletin DC9-32-315 and Boeing Service Bulletin MD90-32-033, Revision 01, both dated October 24, 2000. The commenter states that both of those service bulletins contain statements that they have been approved as an alternative methods of compliance (AMOC) with the requirements of AD 97-02-10. The commenter notes that paragraph (f)(2) of the proposed AD states, "Alternative methods of compliance, approved previously in accordance with AD 97-02-10, amendment 39-9895, are approved as alternative methods of compliance with paragraph (f)(1) of this AD." \n\n\tThe FAA partially agrees. Operators are given credit for work previously performed by means of the phrase in the "Compliance" section of the AD that states, "Required as indicated, unless accomplished previously." Therefore, in the case of this AD, if the required actions have been accomplished before the effective date of this AD, this AD does not require those actions to be repeated. However, we find that clarification with regard to paragraph (f)(2) of this AD is necessary. AMOCs approved previously in accordance with AD 97-02-10 are approved as AMOCs with this AD, not just paragraph (f)(1) of this AD as referenced in the proposed AD. Therefore, we have revised paragraph (f)(2) of this AD accordingly. \n\nRequest To Revise Applicability Statement \n\n\tOne commenter requests that the applicability of the proposed AD be revised to apply to affected airplanes on which upper lock link, part number (P/N) 3914464, has been installed. \n\n\tThe FAA agrees that revising the applicability would clarify that the AD affects those applicable airplanes equipped with upper lock links, P/N 3914464-1, -501, or -503. We have revised the applicability of the final rule to "Model DC-9, DC-9-80, and C-9 series airplanes; Model MD-88 airplanes; and Model MD-90 airplanes; as listed in Boeing Service Bulletins DC9-32-315, and MD90-32-033, both Revision 01, dated October 24, 2000; certificated in any category; equipped with upper lock links, P/N 3914464-1, -501, or -503." In addition, we have revised the P/N of those links in paragraphs (a) and (c)(2)(iii) of the final rule to include the specific dash numbers. \n\nRequest To Revise the Applicability of Certain Paragraphs \n\n\tOne commenter requests that the applicability of paragraphs (a)(1) and (a)(2) of the proposed AD be revised to include a reference to paragraph (c) of AD 97-02-10, in addition to the reference to paragraph (c)(1) of AD 97-02-10. The commenter is concerned that there is a time gap between inspections required by paragraph (c) of AD 97-02-10 and those required by paragraphs (a)(1) and (a)(2) of the proposed AD. \n\n\tThe FAA does not agree. We did not reference paragraph (c) of AD 97-02-10 in the applicability of paragraph (a)(1) or (a)(2) of the proposed AD because that paragraph only requires an initial inspection. The follow-on (i.e., repetitive inspections) and corrective (i.e., replacement) actions occur in paragraph (c)(1) of AD 97-02-10. \n\n\tThe FAA's intent in paragraph (a)(1) of this AD is to ensure that operators that have accomplished the inspection per paragraph (c)(1) of AD 97-02-10 will accomplish the required removal and inspections "before 5,000 landings since the last inspection done per paragraph (c)(1) of AD 97-02-10, or within 90 days after the effective date of this AD, whichever occurs later." If an airplane accumulates 5,000 landings just after the effective date of this AD, then the operator would have 90 days to accomplish the AD. \n\n\tThe FAA's intent in paragraph (a)(2) of this AD is to ensure that operators that have NOT accomplished the inspection per paragraph (c)(1) of AD 97-02-10 will accomplish the required removal and inspections "within 2,500 landings on the NLG after the effective date of this AD." Those affected by paragraph (a)(2) of this AD include but are not limited to: the upper lock links found to be exempt in AD 97-02-10 and airplanes that have been added to the applicability of this AD, which were NOT subject to the requirements of AD 97-02-10. \n\n\tIn light of these findings, the FAA finds that no change to the final rule is necessary in this regard. \n\nRequest for an Alternative Method of Compliance \n\n\tOne commenter requests that all areas of the proposed AD that specify reidentifying the lock link with an "F" after the part number include a "compressive vibro-peening etch" method in addition to the electro chemical deep etch method identified in the proposed AD. The commenter states that the results of a Boeing stress analysis revealed that, "although an electro chemical deep etch process is the preferred method, the use of a vibro-peening, compressing tool to scribe an "F" after the part number will not reduce the overall strength or fatigue life of the unit." The commenter also notes that McDonnell Douglas Service Bulletin DC9-32-315, dated March11, 1999, describes procedures for a non-descript procedure "electro etch" to apply an "F" after the part number, and that it used a "vibro-peening" tool to etch the "F" in the material on all of its airplanes. \n\n\tThe FAA does not agree. As discussed in the preamble of the supplemental NPRM, Revision 01 of Boeing Service Bulletin DC9-32-315, dated October 24, 2000, redefines the type of etching method to be used when marking certain parts as "electro chemical deep etch method." We find only the electro chemical deep etch method to be acceptable for compliance with the reidentification requirements of this AD based on the testing that Boeing has done to support this method. At this time, Boeing has not conducted sufficient testing of the compressive vibro-peening process. \n\nRequest To Revise Certain Compliance Times \n\n\tFor clarification purposes, one commenter requests that the compliance time specified in paragraphs (a)(2) and (d) of the proposed AD be revised to within 2,500 landings on the NLG "upper lock link." The FAA concurs and has revised those paragraphs of the final rule accordingly. \n\nRequest To Remove Requirement for Black Stripe \n\n\tOne commenter requests that paragraph (c)(2)(ii) of the proposed AD be revised to include the following statement: "If an operator can track the location and limits of each individual link, then painting of the black stripe is not necessary." The commenter states that adding a black paint strip to the non-die forged link will add no value to the inspection and replacement tracking of the part for ABX. \n\n\tThe FAA does not agree. The black stripe is used to distinguish the upper lock links made from plate or bar material that are being repetitively inspected until they are replaced. We have confidence that operators have the capability to track these parts. However, we have determined that the black stripe should be painted adjacent to the part number to distinguish the upper lock link from other parts. \n\nRequest for Clarification \n\n\tOne commenter would like confirmation that if no manufacturer's serial number is found stamped on the upper lock link, the link is not from the affected lot of hand forged links. \n\n\tThe FAA agrees with the commenter that if no manufacturer's serial number is found stamped on the upper lock link, the link is not from the affected lot of hand forged links. Therefore, operators must accomplish the etch inspection required by paragraph (c) of this AD, as specified in paragraph (b)(1) of this AD. \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 2,100 Model DC-9, DC-9-80, and C-9 series airplanes; Model MD-88airplanes; and Model MD-90 airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,400 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 inspections of the NLG upper lock link, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection required by this AD on U.S. operators is estimated to be $84,000, or $60 per airplane. \n\n\tIt will take approximately 4 work hours per airplane to accomplish each required replacement of the NLG upper lock link, at an average labor rate of $60 per work hour. Required parts will cost approximately $5,803 per airplane. Based on these figures, the cost impact of each replacement required by this AD on U.S. operators is estimated to be $8,460,200, or $6,043 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132. \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. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by removing amendment 39-9895 (62 FR 3781, January 27, 1997), and by adding a new airworthiness directive (AD), amendment 39-12658, to read as follows: