AD 98-22-13

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, and -40 series airplanes; and certain C-9 (military) series airplanes. This amendment requires modifying the piping of the potable water system. This amendment is prompted by reports of ice forming on the control cables in the wheel well of the left main landing gear due to the freezing and rupturing of undrained potable water pipes. The actions specified by this AD are intended to prevent such ice formation, which could render the slat, aileron, and spoiler flight controls inoperative, and consequently could result in reduced controllability of the airplane.

Final rule.

98-22-13 McDONNELL DOUGLAS: Amendment 39-10860. Docket 97-NM-132-AD. \n\n\tApplicability: Model DC-9-10, -20, -30, and -40 series airplanes, and C-9 (military) series airplanes; having a pressurized or unpressurized potable water piping system installed over the center wing box; 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 (c) 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 ice from forming on the control cables in the wheel well of the left main landing gear, which could render the slat, aileron, and spoiler flight controls inoperative, and consequently could result in reduced controllability of the airplane, accomplish the following: \n\n\t(a)\tExcept as provided by paragraph (b) of this AD: Within 18 months after the effective date of this AD, modify the piping of the potable water system in accordance with McDonnell Douglas DC-9 Service Bulletin 38-27, Revision 1, dated May 16, 1978. \n\n\t(b)\tFor any period during which the potable water piping system is deactivated, the actions specified in paragraph (a) of this AD are not required. \n\n\t(c)\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(d)\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(e)\tThe actions shall be done in accordance with McDonnell Douglas Service Bulletin 38-27, Revision 1, dated May 16, 1978. 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 ACO, 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(f)\tThis amendment becomes effective on December 2, 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 all McDonnell Douglas Model DC-9-10, -20, -30, and -40 series airplanes; and all C-9 (military) series airplanes; was published in the Federal Register on September 15, 1997 (62 FR 48189). That action proposed to require modifying the piping of the potable water system. \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. \n\nRequest to Revise Applicability \n\n\tOne commenter requests that the applicability of the proposed AD be revised. The commenter states that the AD should exclude airplanes on which the pressurized potable water system has been deactivated. In support of this request, the commenter states that airplanes that do not use a pressurized potable water system do not have exposure to the unsafe condition identified in the proposed AD. The commenter adds that the effectivity of McDonnell Douglas DC-9 Service Bulletin 38-27, Revision 1, dated May 16, 1978, which is referenced as the appropriate source of service information in the proposed AD, is limited to airplanes incorporating a pressurized potable water system. \n\n\tThe FAA concurs partially, acknowledging that some operators may have deactivated an affected potable water system or may be using a gravity feed system installed on top of the lavatory. However, the intent of this AD is to prevent freezing water from forming ice on the control cable in the wheel well due to water line breakage over the center wing box area. Therefore, this AD applies to airplanes on which potable water piping systems (either pressurized or unpressurized) are installed over the center wing box area. The applicability of the final rule has been revised accordingly. \n\n\tAlthough modification of the potable water system is required only for airplanes having activated systems, the FAA has determined that the applicability cannot exclude airplanes on which the system has been deactivated, in the event a deactivated system may be subsequently reactivated. However, the final rule has been revised to add a new paragraph (b) to clarify that airplanes are exempt from the modification requirement for any period during which the system is deactivated. \n\nRequest to Revise Specifications of Modification Requirement \n\n\tOne commenter requests that the proposed AD be revised to allow the use of parts other than those specified in the AD. Specifically, the commenter requests that the proposed AD additionally allow the use of hardware that is structurally equivalent to that specified in McDonnell Douglas DC-9 Service Bulletin 38-27, Revision 1, dated May 16, 1978 (the source of service information cited in this AD for accomplishment of the required actions). Further, the commenter requests that the proposed AD allow the use of 1.5-inch-diameter ABS pipe as an alternative to the currently required 1.25-inch-diameter aluminum tube for the shroud. The commenter states that, on some of its airplanes, it already has installed a shroud and hardware that are "equivalent" to the parts specified by the proposed AD, although the part numbers are different. \n\n\tThe FAA does not concur with the commenter's request. The FAA considers it inappropriate to include in an AD various provisions that are applicable to a single operator's unique use of affected airplanes. However, paragraph (c) of this AD contains a provision for requesting approval of an alternative method of compliance to address these types of unique circumstances. \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 570 airplanes of the affected design in the worldwide fleet. The FAA estimates that 316 airplanes of U.S. registry will be affected by this AD, that it will take approximately 20 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $4,000 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $1,643,200, or $5,200 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. However, the FAA has been advised that 219 U.S.-registered airplanes are incompliance in accordance with the requirements of this AD. Therefore, the future economic cost impact of this rule on U.S. operators is now $504,400. \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\n Adoption 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. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: