AD 94-23-01

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10 series airplanes, that currently requires inspection of the wing rear spar lower cap aft tang fastener and the wing trailing edge access door sill to detect fatigue cracking, and repair, if necessary. This amendment requires installation of a crack preventative modification of the wing rear spar lower cap, and follow-on inspections. This amendment is prompted by reports of additional cracking found in the current inspection area. The actions specified by this AD are intended to prevent propagation of cracks in the subject area, which could compromise the structural integrity of the airplane.

Final rule.

94-23-01 McDONNELL DOUGLAS: Amendment 39-9063. Docket 94-NM-51-AD. Supersedes AD 91-21-05, Amendment 39-8052. \n\n\tApplicability: Model DC-10-10, -10F, and -15 series airplanes, fuselage numbers through 379 inclusive; and Model DC-10-30, -30F, and -40 series airplanes, fuselage numbers through 275 inclusive, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo ensure the structural integrity of these airplanes, accomplish the following: \n\n\t(a)\tExcept as provided in paragraphs (b) through (e) of this AD, prior to the accumulation of 7,000 total landings or within 30 days after October 23, 1991 (the effective date of AD 91-21-05, amendment 39-8051), whichever occurs later, conduct the initial inspections specified in either paragraph (a)(1), (a)(2), or (a)(3) of this AD. \n\n\t\t(1)\tConduct an eddy current inspection of the wing rear spar lower cap aft tang, and a dye penetrant inspection of the wing trailing edge access door sill located between Xors=417.000 and Xors=424.000, in accordance with Option III of McDonnell Douglas Alert Service Bulletin A57- 123, dated July 25, 1991, or Revision 1, dated June 8, 1993. In addition, within 1,500 landings after performing the eddy current and dye penetrant inspections, conduct the inspections specified in either paragraph (a)(2) or (a)(3) of this AD, and repeat them thereafter as indicated.\n\nOr \n\n\t\t(2)\tConduct an ultrasonic inspection of the area around the six wing rear spar lower cap aft tang fastener holes, and a dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=424.000, in accordance with Option II of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 1993. Repeat these inspections thereafter at intervals not to exceed 1,900 landings until the modification required by paragraph (g) of this AD is accomplished. Or \n\n\t\t(3)\tConduct an eddycurrent inspection of the six wing rear spar lower cap aft tang fastener holes, and a dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=424.000, in accordance with Option I of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 1993. Repeat these inspections thereafter at intervals not to exceed 3,300 landings until the modification required by paragraph (g) of this AD is accomplished. \n\n\t(b)\tThe requirements of paragraph (c) of this AD apply to airplanes on which both of the following actions have been accomplished: \n\n\t\t(1)\tA dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=422.000 has been accomplished prior to October 23, 1991, in accordance with McDonnell Douglas Service Bulletin 57-61, Revision 2, dated August 15, 1990; and \n\n\t\t(2)\tAn eddy current inspection of the wing rear spar lower cap aft tanghas been accomplished prior to October 23, 1991, per DC-10 Supplemental Inspection Document, Principal Structural Element (PSE) 57.10.007 and 57.10.008, in accordance with McDonnell Douglas Service Bulletin 57-61, Revision 2, dated August 15, 1990. \n\n\t(c)\tFor airplanes specified in paragraph (b) of this AD: Conduct the initial inspections specified in either paragraph (c)(1) or (c)(2) of this AD within 1,500 landings after accomplishing the inspections (dye penetrant and eddy current) specified in paragraph (b) of this AD, or within 30 days after October 23, 1991, whichever occurs later. \n\n\t\t(1)\tConduct an ultrasonic inspection of the area around the six wing rear spar lower cap aft tang fastener holes, and a dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=424.000, in accordance with Option II of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 1993. Repeat theseinspections thereafter at intervals not to exceed 1,900 landings until the modification required by paragraph (g) of this AD is accomplished. Or \n\n\t\t(2)\tConduct an eddy current inspection of the six wing rear spar lower cap aft tang fastener holes, and a dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=424.000, in accordance with Option I of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 1993. Repeat these inspections thereafter at intervals not to exceed 3,300 landings until the modification required by paragraph (g) of this AD is accomplished. \n\n\t(d)\tThe requirements of paragraph (e) of this AD apply to airplanes on which both of the following actions have been accomplished: \n\n\t\t(1)\tA dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=422.000 has been accomplished prior to October 23, 1991, in accordance with McDonnell Douglas Service Bulletin 57-61, Revision 2, dated August 15, 1990; and \n\n\t\t(2)\tAn eddy current inspection of the wing rear spar lower cap aft tang fastener holes located between stations Xors=417.000 and Xors=422.000 has been accomplished prior to October 23, 1991, per DPS 4.735-9, in accordance with McDonnell Douglas Service Bulletin 57-61, Revision 2, dated August 15, 1990. \n\n\t(e)\tFor airplanes specified in paragraph (d) of this AD: Conduct the initial inspections specified in either paragraph (e)(1) or (e)(2) of this AD within 3,300 landings after the accomplishment of the inspection specified in paragraph (d)(1) of this AD, or within 30 days after October 23, 1991, whichever occurs later. \n\n\t\t(1)\tConduct an ultrasonic inspection of the area around the six wing rear spar lower cap aft tang fastener holes, and a dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=424.000, in accordance with Option II of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 1993. Repeat these inspections thereafter at intervals not to exceed 1,900 landings until the modification required by paragraph (g) of this AD is accomplished. Or \n\n\t\t(2)\tConduct an eddy current inspection of the six wing rear spar lower cap aft tang fastener holes, and a dye penetrant inspection of the wing trailing edge access door sill located between stations Xors=417.000 and Xors=424.000, in accordance with Option I of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 1993. Repeat these inspections thereafter at intervals not to exceed 3,300 landings until the modification required by paragraph (g) of this AD is accomplished. \n\n\t(f)\tIf any crack(s) is found during any inspection conducted in accordance with paragraphs (a) through (e) of this AD, prior to further flight, repair in a manner approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\t(g)\tPrior to the accumulation of 10,000 total landings, or within 5 years after the effective date of this AD, whichever occurs later, accomplish the crack preventative modification in accordance with McDonnell Douglas Service Bulletin 57-123, dated June 8, 1993. Accomplishment of this modification constitutes terminating action for the inspection requirements of paragraphs (a) through (e) of this AD. \n\n\t(h)\tPrior to the accumulation of 10,000 total landings after the accomplishment of the crack preventative modification required by paragraph (g) of this AD, conduct an inspection of the wing rear spar lower cap in accordance with McDonnell Douglas Service Bulletin 57-123, dated June 8, 1993. Repeat this inspection thereafter in accordance with the following schedule. Any crack(s) found during any inspection required by this paragraph must be repaired, prior to further flight, in accordance with a method approved by the Manager, Los Angeles ACO, FAA, Transport Airplane Directorate. \n\n\t\t(1)\tFor Model DC-10-10, -10F, and -15 series airplanes: Repeat the inspection at intervals not to exceed 4,550 landings. \n\n\t\t(2)\tFor Model DC-10-30 and -30F series airplanes: Repeat the inspection at intervals not to exceed 2,810 landings. \n\n\t\t(3)\tFor Model DC-10-40 series airplanes: Repeat the inspection at intervals not to exceed 3,400 landings. \n\n\t(i)\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 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: 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(j)\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(k)\tThe actions shall be done in accordance with McDonnell Douglas Alert Service Bulletin A57-123, Revision 1, dated June 8, 1993; McDonnell Douglas Service Bulletin 57-123, dated June 8, 1993; and McDonnell Douglas Service Bulletin 57-61, Revision 2, dated August 15, 1990. The incorporation by reference of McDonnell Douglas Alert Service Bulletin 57-61, dated July 25, 1991, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51 as of October 23, 1991 (56 FR 50650, October 8, 1991). The incorporation by reference of the remainder of the service documents listed above is 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 McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, California 90801-1771, Attention: Business Unit Manager, Technical Administrative support, Dept. L51, M.C. 2-98. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles ACO, Transport Airplane Directorate, 3229 East Spring Street, Long Beach, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(l)\tThis amendment becomes effective on December 15, 1994.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 91-21-05, amendment 39-8052 (56 FR 50650, October 8, 1991), which is applicable to certain McDonnell Douglas Model DC-10 series airplanes was published in the Federal Register on July 22, 1994 (59 FR 37443). That action proposed to require installation of a crack preventative modification of the wing rear spar lower cap, and follow-on inspections. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the two comments received. \n\n\tBoth commenters support the proposed rule. \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 as proposed. \n\n\tThere are approximately 282 Model DC-10 series airplanes of the affected design in the worldwide fleet.The FAA estimates that 175 airplanes of U.S. registry will be affected by this AD. \n\n\tThe currently required inspections take approximately 8 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the total cost impact of the current inspection requirements of this AD on U.S. operators is estimated to be $84,000, or $480 per airplane, per inspection. \n\n\tThe modification will take approximately 12 work hours to accomplish, at an average labor rate of $60 per work hour. Required parts will cost between $3,730 and $6,730 per airplane, depending upon the airplane model. Based on these figures, the total cost impact of the modification requirement of this AD on U.S. operators is estimated to be between $4,450 and $7,450 per airplane. \n\n\tThe post-modification inspections will take approximately 12 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the total cost impactof the post-modification inspection requirements of this AD on U.S. operators is estimated to be $126,000, or $720 per airplane, per inspection. \n\n\tThe total 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\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 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.\tThe authority citation for part 39 continues to read as follows: \n\nAuthority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.106(g); and 14 CFR 11.89. \n\n§ 39.13 - (Amended) \n\n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: