AD 98-15-15

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes, that currently requires an inspection to detect chafing on the FIREX pipe assembly of the number one engine; and either repair of chafed pipe assemblies or replacement of the chafed pipe assemblies with new pipe assemblies; and modification of the FIREX and the pneumatic sense pipe assembly clamp marriage. This amendment revises the applicability of the existing AD to include additional airplanes and remove others. This amendment is prompted by reports of incidents in which the pneumatic sense pipe chafed against the FIREX supply pipe of the number one engine. The actions specified by this AD are intended to prevent chafing of the FIREX supply pipe, which could result in a hole in the pipe and consequently prevent the proper distribution of the fire extinguishing agent within the nacelle in the event of a fire.

Final rule.

98-15-15 MCDONNELL DOUGLAS: Amendment 39-10666. Docket 97-NM-105-AD. Supersedes AD 95-12-25, Amendment 39-9278. \n\n\tApplicability: Model DC-9-30, -40, and -50 series airplanes; Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) series airplanes; Model MD-88 airplanes; and C-9 (military) series airplanes; as listed in McDonnell Douglas Service Bulletin DC9-26-025, Revision 04, dated April 30, 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 (b) of this AD. The request should include an assessment of the effect of themodification, 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 chafing of the FIREX supply pipe, which could result in a hole in the pipe and consequently prevent the proper distribution of the fire extinguishing agent within the nacelle in the event of a fire, accomplish the following: \n\n\t(a)\tWithin 8 months after the effective date of this AD, perform an inspection to detect chafing of the FIREX pipe assembly of the number one engine, in accordance with McDonnell Douglas DC-9 Service Bulletin 26-25, dated May 25, 1994; McDonnell Douglas DC-9 Service Bulletin 26-25, Revision 1, dated September 30, 1994; McDonnell Douglas DC-9 Service Bulletin 26-25, Revision 2, dated April 18, 1995; McDonnell Douglas Service Bulletin DC9-26-025, Revision 03, dated July 25,1996; McDonnell Douglas Service Bulletin DC9-26-025, Revision 04, dated April 30, 1997; or McDonnell Douglas Service Bulletin DC9-26-025, Revision 05, dated May 29, 1998. \n\n\t\t(1)\tIf any chafing is detected, prior to further flight, accomplish paragraphs (a)(1)(i) and (a)(1)(ii) of this AD in accordance with the service bulletin. Where there are differences between the requirements of this AD and the procedures specified in the service bulletin, the AD prevails. \n\n\t\t\t(i)\tEither repair chafed pipe assemblies or replace chafed pipe assemblies with new or serviceable pipe assemblies. And \n\n\t\t\t(ii)\tModify the FIREX and the pneumatic sense pipe assembly clamp marriage. \n\n\t\t(2)\tIf no chafing is detected, prior to further flight, modify the FIREX and the pneumatic sense pipe assembly clamp marriage in accordance with the service bulletin. \n\n\t(b)\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 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(c)\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(d)\tThe actions shall be done in accordance with McDonnell Douglas DC-9 Service Bulletin 26-25, dated May 25, 1994; McDonnell Douglas DC-9 Service Bulletin 26-25, Revision 1, dated September 30, 1994; McDonnell Douglas DC-9 Service Bulletin 26-25, Revision 2, dated April 18, 1995; McDonnell Douglas Service Bulletin DC9-26-025, Revision 03, dated July 25, 1996; McDonnell Douglas Service Bulletin DC9-26-025, Revision 04, dated April 30, 1997; or McDonnell Douglas Service Bulletin DC9-26-025, Revision 05, dated May 29, 1998. \n\n\t\t(1)\tThe incorporation by reference of McDonnell Douglas DC-9 Service Bulletin 26-25, dated May 25, 1994; McDonnell Douglas Service Bulletin DC9-26-025, Revision 03, dated July 25, 1996; and McDonnell Douglas Service Bulletin DC9-26-025, Revision 04, dated April 30, 1997; and McDonnell Douglas Service Bulletin DC9-26-025, Revision 05, dated May 29, 1998; is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. \n\n\t\t(2)\tThe incorporation by reference of McDonnell Douglas DC-9 Service Bulletin 26-25, Revision 1, dated September 30, 1994; and McDonnell Douglas DC-9 Service Bulletin 26-25, Revision 2, dated April 18, 1995; was approved previously by the Director of the Federal Register as of July 24, 1995 (60 FR 32579, June 23, 1995). \n\n\t\t(3)\tCopies 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(e)\tThis amendment becomes effective on August 25, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 95-12-25, amendment 39-9278 (60 FR 32579, June 23, 1995), which is applicable to certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes, was published in the Federal Register on January 5, 1998 (63 FR 174). The action proposed to continue to require an inspection to detect chafing on the FIREX pipe assembly of the number one engine; and either repair of chafed pipe assemblies or replacement of the chafed pipe assemblies with new pipe assemblies; and modification of the FIREX and the pneumatic sense pipe assembly clamp marriage. \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 single comment received. \n\n\tThe commenter supports the proposed rule. \n\nExplanation of Changes to This Final RuleSince the issuance of the proposal, the FAA has reviewed and approved McDonnell Douglas Service Bulletin DC9-26-025, Revision 05, dated May 29, 1998. This revision is essentially the same as McDonnell Douglas Service Bulletin DC9-26-025, Revision 04, dated April 30, 1997; however, minor edits have been incorporated. The FAA has revised this final rule to reference Revision 05 as an additional source of service information for accomplishment of the required actions. \n\nConclusion \n\n\tAfter careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 1,691 McDonnell Douglas Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes of the affected design in the worldwide fleet. The FAA estimates that 834 airplanes of U.S. registry will be affected by this AD. \n\n\tThe actions that are currently required by AD 95-12-25, and retained in this AD, take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. The cost of required parts will be nominal. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $50,040, or $60 per airplane. \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, 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 AmendmentAccordingly, 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. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by removing amendment 39-9278 (60 FR 32579, June 23, 1995), and by adding a new airworthiness directive (AD), amendment 39-10666, to read as follows: