# Airworthiness Directives; McDonnell Douglas Model DC-10-10, -15, -30, and -40 Series Airplanes and KC-10A (Military) Airplanes > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A94-7493 ## Record - **Collection:** Federal Register - **Document type:** Uncategorized Document - **Published:** March 30, 1994 ## Text DEPARTMENT OF TRANSPORTATION 14 CFR Part 39 [Docket No. 93-NM-221-AD] Airworthiness Directives; McDonnell Douglas Model DC-10-10, -15, -30, and -40 Series Airplanes and KC-10A (Military) 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 DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military) airplanes. This proposal would require inspections to detect fatigue- related cracking in certain areas of the horizontal stabilizer; and repair of cracked parts. This proposal would also require installation of terminating modifications, which, when accomplished, would eliminate the repetitive inspections. This proposal is prompted by reports of fatigue-related cracks found on the horizontal stabilizer. The actions specified by the proposed AD are intended to prevent loss of the load carrying and fail safe capability of the horizontal stabilizer, damage to the adjacent structure, and subsequent reduced structural integrity of the airplane. DATES: Comments must be received by May 23, 1994. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 93-NM-221-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, CA 90801-1771, Attention: Business Unit Manager, Technical Administrative Support, Dept. L51, M.C. 2-98. 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 (ACO), 3229 East Spring Street, Long Beach, California. FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los Angeles ACO, 3229 East Spring Street, Long Beach, California 90806- 2425; telephone (310) 988-5324; fax (310) 988-5210. 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 93-NM-221-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-103, Attention: Rules Docket No. 93-NM-221-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion The manufacturer reports that fatigue-related cracks have been found on the horizontal stabilizer on several McDonnell Douglas Model DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military) airplanes. One operator reported two instances of fatigue-related cracks on the forward spar upper cap near the closing rib on the horizontal stabilizer on airplanes that had accumulated approximately 22,643 landings. Two operators reported three cases of fatigue-related cracks in the forward upper skin panel in the outboard section of the horizontal stabilizer on airplanes that had accumulated between 17,339 and 19,627 total landings. This skin panel is located immediately aft of (and attaches to) the forward spar upper cap on the horizontal stabilizer. Investigation by the manufacturer has revealed that these cracks are the result of fatigue-related stress. Fatigue-related cracks in the outboard section of the horizontal stabilizer, if not detected and corrected in a timely manner, could result in loss of the load carrying and fail safe capability of the forward spar upper caps and the forward upper skin panels, damage to the adjacent structure, and subsequent reduced structural integrity of the airplane. The FAA has reviewed and approved McDonnell Douglas DC-10 Service Bulletin 55-24, dated October 25, 1993, that describes procedures for repetitive eddy current inspections to detect fatigue-related cracking in the forward spar upper cap of the horizontal stabilizer. The service bulletin also describes procedures for accomplishment of a preventative modification for the forward spar upper cap. The preventative modification entails rework of the fastener holes of the forward spar upper cap. Incorporation of this preventative modification would eliminate the need for repetitive inspections of the forward spar upper cap. Accomplishment of this preventative modification will restore the structural integrity of the forward spar upper cap. The FAA has also reviewed and approved McDonnell Douglas DC-10 Service Bulletin 55-25, dated October 25, 1993, that describes procedures for performing repetitive eddy current inspections to detect fatigue-related cracking in the forward upper skin panel of the horizontal stabilizer. The service bulletin also describes procedures for accomplishment of a preventative modification for the forward upper skin panel. The preventative modification entails rework of the fastener holes of the forward upper skin panel. Incorporation of this preventative modification would eliminate the need for repetitive inspections of the forward upper skin panel. Accomplishment of this preventative modification will restore the structural integrity of the forward upper skin panel. 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 repetitive eddy current inspections to detect fatigue-related cracking on the forward spar upper caps and the forward upper skin panels in the outboard section of the horizontal stabilizer. The proposed AD would also require that cracked parts be repaired in accordance with a method approved by the FAA. This proposal would also require accomplishment of preventative modifications, which, when accomplished, would terminate the repetitive inspections of the forward spar upper caps and the forward upper skin panels. The inspections and modifications would be required to be accomplished in accordance with the service bulletins described previously. There are approximately 427 Model DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military) airplanes of the affected design in the worldwide fleet. The FAA estimates that 241 airplanes of U.S. registry would be affected by this proposed AD. The accomplishment of the proposed inspection would take approximately 3 work hours per airplane, at an average labor charge of $55 per work hour. Based on these figures, the total cost impact of the proposed inspection actions on U.S. operators is estimated to be $39,765, or $165 per airplane, per inspection cycle. The accomplishment of the proposed modification of the forward spar upper cap would take approximately 248 work hours per airplane. Likewise, the accomplishment of the proposed modification of the forward upper skin panel would take approximately 248 work hours per airplane. The average labor rate is $55 per work hour. Required parts would cost approximately $10,600 per airplane. Based on these figures, the total cost impact of the proposed modification actions AD on U.S. operators is estimated to be $9,129,080, or $37,880 per airplane. The FAA recognizes that the proposed modifications would require a large number of work hours to accomplish. However, the 5-year compliance time specified in paragraph (d) of this proposed AD should allow ample time for the modifications to be accomplished coincidentally with scheduled major airplane inspection and maintenance activities, thereby minimizing the costs associated with special airplane scheduling. The total 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. 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 14 CFR part 39 of the Federal Aviation Regulations as follows: PART 39--AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: McDonnell Douglas: Docket 93-NM-221-AD. Applicability: Model DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military) airplanes; as listed in McDonnell Douglas DC-10 Service Bulletins 55-24 and 55-25, both dated October 25, 1993; certificated in any category. Compliance: Required as indicated, unless accomplished previously. To prevent reduced structural integrity of the airplane, accomplish the following: (a) For Model DC-10-10 and -15 series airplanes: Prior to the accumulation of 18,000 total landings, or within 90 days after the effective date of this AD, whichever occurs later, unless previously accomplished within the last 4,500 landings, perform an eddy current inspection to detect fatigue-related cracking of the forward spar upper caps on the horizontal stabilizer, in accordance with McDonnell Douglas Service Bulletin 55-24, dated October 25, 1993. (1) If any crack is detected, prior to further flight, repair the crack in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. After repair, repeat the inspection thereafter at intervals not to exceed 4,500 landings in accordance with the service bulletin. (2) If no crack is detected, repeat the inspection thereafter at intervals not to exceed 4,500 landings in accordance with the service bulletin. (b) For Model DC-10-10 and -15 series airplanes: Prior to the accumulation of 10,000 total landings, or within 120 days after the effective date of this AD, whichever occurs later, unless previously accomplished within the last 4,500 landings, perform an eddy current inspection to detect fatigue-related cracking of the forward upper skin panel of the horizontal stabilizer, in accordance with McDonnell Douglas Service Bulletin 55-25, dated October 25, 1993. (1) If any crack is detected, prior to further flight, repair the crack in accordance with a method approved by the Manager, Los Angeles ACO, FAA, Transport Airplane Directorate. After repair, repeat the inspection thereafter at intervals not to exceed 4,500 landings in accordance with the service bulletin. (2) If no crack is detected, repeat the inspection thereafter at intervals not to exceed 4,500 landings in accordance with the service bulletin. (c) For Model DC-10-30 and -40 series airplanes: Prior to the accumulation of 17,500 total landings, or within 120 days after the effective date of this AD, whichever occurs later, unless previously accomplished within the last 4,500 landings, perform an eddy current inspection to detect fatigue-related cracking of the forward upper skin panel of the horizontal stabilizer, in accordance with McDonnell Douglas Service Bulletin 55-25, dated October 25, 1993. (1) If any crack is detected, prior to further flight, repair the crack in accordance with a method approved by the Manager, Los Angeles ACO, FAA, Transport Airplane Directorate. After repair, repeat the inspection thereafter at intervals not to exceed 4,500 landings in accordance with the service bulletin. (2) If no crack is detected, repeat the inspection thereafter at intervals not to exceed 4,500 landings in accordance with the service bulletin. (d) For all airplanes: Within 5 years after the effective date of this AD, install the preventative modifications for the forward spar upper cap on the horizontal stabilizer, in accordance with McDonnell Douglas Service Bulletin 55-24, dated October 25, 1993; and for the forward upper skin panel on the horizontal stabilizer, in accordance with McDonnell Douglas Service Bulletin 55-25, dated October 25, 1993. Accomplishment of these preventative modifications in accordance with these service bulletins constitutes terminating action for the repetitive inspections required by this AD. (e) 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 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: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. (f) Special flight permits may be issued in accordance with Federal Aviation Regulations (FAR) 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 March 24, 1994. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 94-7493 Filed 3-29-94; 8:45 am] BILLING CODE 4910-13-U --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-7493. Public record. Not legal advice.