[Federal Register Volume 64, Number 207 (Wednesday, October 27, 1999)] [Proposed Rules] [Pages 57789-57790] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 99-28079] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 99-NM-209-AD] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas Model MD-90 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-90 series airplanes. This proposal would require a one-time detailed visual inspection to detect fatigue cracking of certain longerons and the attaching frames of the lower left nose; and repair, if necessary. The proposal also would require installation of a preventive modification. This proposal is prompted by several reports of fatigue cracking of certain longerons and the attaching frames. The actions specified by the proposed AD are intended to prevent such fatigue cracking, which could result in reduced structural integrity of the fuselage, and consequent loss of pressurization of the airplane. DATES: Comments must be received by December 13, 1999. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-209-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule 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). This information may be examined 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. FOR FURTHER INFORMATION CONTACT: Carl Fountain, Aerospace Engineer, Airframe Branch, ANM-120L; FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone (562) 627-5222; fax (562) 627-5210. SUPPLEMENTARY INFORMATION: Comments Invited Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NM-209-AD.'' The postcard will be date stamped and returned to the commenter. Availability of NPRMs Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-209-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion The FAA has received reports indicating that cracking of the fuselage longerons-to-frame attachment holes occurred on three McDonnell Douglas Model DC-9 series airplanes. The fatigue cracking was found between longerons 22 though 26 on the left side at stations Y=160.000 and Y=200.000. These airplanes had accumulated between 59,110 and 74,445 total flight cycles. The cracking of the longeron segments has been attributed to fatigue. Such fatigue cracking, if not corrected, could result in reduced structural integrity of the fuselage, and consequent loss of pressurization of the airplane. The fuselage longerons-to-frame attachments of McDonnell Douglas Model MD-90 series airplanes are similar to those of the affected McDonnell Douglas Model DC-9 series airplanes. Therefore, the Model MD- 90 may be subject to the same unsafe condition. Other Relevant Rulemaking On November 20, 1998, the FAA issued AD 98-24-33, amendment 39- 10919 (63 FR 66739, December 3, 1998), applicable to certain McDonnell Douglas DC-9 and MD-88 series airplanes, to require a one-time visual inspection to detect fatigue cracks between longerons 22 through 26 and the attaching frames, and corrective action, if necessary. However, this proposed AD would not affect the current requirements of that previously issued AD. Explanation of Relevant Service Information The FAA has reviewed and approved McDonnell Douglas Service Bulletin MD90-53-004, dated August 20, 1998, which describes procedures for a one-time detailed visual inspection to detect cracking of longerons 22 through 26 and the attaching frames at stations Y=160.000 and Y=200.000 of the lower left nose, and repair, if necessary. The service bulletin also provides procedures for a preventive modification (i.e., installation of clips and doublers under longeron flanges and shims longeron) to relieve preloads. Explanation of Requirements of Proposed Rule Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously. Cost Impact There are approximately 7 airplanes of the affected design in the worldwide fleet. The FAA estimates that 6 airplanes of U.S. registry would be affected by this proposed AD. [[Page 57790]] It would take approximately 1 work hour per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $360, or $60 per airplane. It would take approximately 6 work hours per airplane to accomplish the proposed modification, at an average labor rate of $60 per work hour. Parts would cost approximately $312 per airplane. Based on these figures, the cost impact of the modification proposed by this AD on U.S. operators is estimated to be $4,032, or $672 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. Regulatory Impact The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. The Proposed Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: PART 39--AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: McDonnell Douglas: Docket 99-NM-209-AD. Applicability: Model MD-90 series airplanes, as listed in McDonnell Douglas Service Bulletin MD90-53-004, dated August 20, 1998; certificated in any category. Note 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 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. Compliance: Required as indicated, unless accomplished previously. To prevent fatigue cracking of longerons 22 through 26 and the attaching frames, which could result in reduced structural integrity of the fuselage, and consequent loss of pressurization of the airplane; accomplish the following: Inspection and Modification (a) Prior to the accumulation of 40,000 total landings, or within 24 months after the effective date of this AD, whichever occurs later: Perform a detailed visual inspection to detect cracking of longerons 22 through 26 (inclusive) and the respective attaching frames at station frames Y=160.000 and Y=200.000 of the left lower nose, in accordance with McDonnell Douglas Service Bulletin MD90-53-004, dated August 20, 1998. Note 2: For the purposes of this AD, a detailed visual inspection is defined as: ``An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.'' (1) If no cracking is detected: Prior to further flight, install clips and doublers under the longeron flanges and shim the longerons in accordance with the service bulletin. (2) If any cracking is detected: Prior to further flight, repair the cracks and install clips and doublers under the longeron flanges and shim the longerons in accordance with the service bulletin. Alternative Methods of Compliance (b) 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, 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. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, Los Angeles ACO. Special Flight Permits (c) 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. Issued in Renton, Washington, on October 21, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-28079 Filed 10-26-99; 8:45 am] BILLING CODE 4910-13-U