92-11-10 MCDONNELL DOUGLAS: Amendment 39-8260. Docket No. 91-NM-232-AD. Supersedes AD 91-13-09, Amendment 39-7040. \n\n\tApplicability: Model DC-9-20, -30, -40, -50, and C-9 (Military) series airplanes; which correspond to factory serial numbers listed in McDonnell Douglas Service Bulletin 27-196, Revision 1, dated September 28, 1984, or Revision 2, dated December 17, 1990; McDonnell Douglas Service Bulletin 27-250, dated August 29, 1984, or Revision 1, dated October 18, 1984, or Revision 2, dated January 3, 1990; and McDonnell Douglas Alert Service Bulletin A27-250, Revision 3, dated May 15, 1991; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\tTo detect cracks and prevent failure of the slat drive mechanism and its interrelated structure, accomplish the following: \n\n\t(a)\tWithin 20 days or 135 landings, whichever occurs first after January 10, 1985 (the effective date of AD 84-24-03, Amendment 39-4956), inspect the left and right actuator slat drive mechanism in accordance with McDonnell Douglas Service Bulletin 27-196, Revision 1, dated September 28, 1984, or Revision 2, dated December 17, 1990. \n\n\t\t(1)\tIf no cracks are found, no further inspection is required. \n\n\t\t(2)\tIf a crack is found, and the crack is less than one inch in length, continue to inspect the actuator slat drive shaft at intervals not to exceed 1,600 landings in accordance with the service bulletin. \n\n\t\t(3)\tIf a crack is found, and the crack is one inch or greater in length, prior to further flight, replace the actuator slat drive shaft in accordance with Condition II specified in the service bulletin. Such replacement constitutes terminating action for the inspections required by paragraph (a)(2) of this AD. \n\n\t(b)\tWithin 20 days or 135 landings, whichever occurs first after January 10, 1985, inspect the forward slat drive drums' bellcrank shafts that have accumulated 4,000 or more landings since new or last overhaul.(1)\tIf no cracks are detected, continue to inspect the slat drive drum bellcrank shaft for cracks at intervals not to exceed 1,500 landings as shown in Figure 1 of McDonnell Douglas Service Bulletin 27-250, dated August 29, 1984; Revision 1, dated October 18, 1984; or Revision 2, dated January 3, 1990. \n\n\t\t(2)\tIf cracks are found, prior to further flight, replace the slat drive drum bellcrank shaft in accordance with Condition II of the service bulletin. Such replacement constitutes terminating action for the repetitive inspection requirements of paragraph (b)(1) of this AD. \n\n\t(c)\tWithin 500 landings after July 8, 1991 (the effective date of AD 91-13-09, Amendment 39-7040), or at the next scheduled inspection in accordance with paragraph (b) of this AD, whichever occurs earlier, inspect the slat drive drums' bellcrank shafts for cracks, in accordance with McDonnell Douglas Alert Service Bulletin A27-250, Revision 3, dated May 15, 1991. This inspection constitutes terminating action for the repetitive inspection requirements of paragraph (b)(1) of this AD. \n\n\t\t(1)\tIf no cracks are found, repeat the inspection of the slat drive drum bellcrank shaft for cracks at intervals not to exceed 750 landings, in accordance with the alert service bulletin. \n\n\t\t(2)\tIf cracks are found, prior to further flight, replace the slat drive drum bellcrank shaft with a new drum shaft, P/N 5920212-505, in accordance with Condition II specified in the alert service bulletin. Such replacement constitutes terminating action for the repetitive inspection requirements of paragraph (c)(1) of this AD. \n\n\t(d)\tIf cracks are found in locations in the slat drive shaft(s) other than those specified in McDonnell Douglas Service Bulletin 27-196, Revision 1 or 2; and McDonnell Douglas Alert Service Bulletin A27-250, Revision 3; prior to further flight, replace or rework the cracked component(s) in a manner approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate. \n\n\t(e)\tReplacement of both the actuator slat drive mechanism and the slat drive drum bellcrank shaft in accordance with Condition II of the following service bulletins, as applicable, constitutes terminating action for the requirements of this AD: \n\t\n\nMcDonnell Douglas \nService Bulletin Number\nRevision Level\n\tDate \n27-196\t\t\nRevision 1\nSeptember 28, 1984 \n\nRevision 2\t\nDecember 17, 1990 \n\n\n\n27-250\t\nOriginal\t\nAugust 29, 1984 \n\nRevision 1\t\nOctober 18, 1984 \n\nRevision 2\t\nJanuary 3, 1990 \n\n\n\nA27-250\t\t\nRevision 3\nMay 15, 1991 \n\t\n\t(f)\tWithin 18 months or 2,250 flight cycles after the effective date of this AD, whichever occurs later, replace the slat drive drum bellcrank shaft with a new drum shaft, P/N 5920212-505, in accordance with Condition II specified in McDonnell Douglas Alert Service Bulletin 27-250, Revision 3, dated May 15, 1991. Such replacement constitutes terminating action for the repetitive inspection requirements of paragraphs (b)(1) and (c)(1) of this AD. \n\n\t(g)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. \n\n\t(h)\tAn alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. The request shall be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment 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 airworthiness directive, if any, may be obtained from the Los Angeles ACO. \n\n\t(i)\tUpon the request of an operator, an FAA Maintenance Inspector, subject to prior approval by the Manager, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, may adjust the inspection times specified in this AD to permit compliance at an established inspection period of that operator if the request contains substantiating data to justify the change for that operator. \n\n\t(j)\tThe inspection and replacement requirements shall be done in accordance with McDonnell Douglas Service Bulletin 27-196, Revision 1, dated September 28, 1984, or Revision 2, dated December 17, 1990; McDonnell Douglas Service Bulletin 27-250, dated August 29, 1984, or Revision 1, dated October 18, 1984, or Revision 2, dated January 3, 1990; and McDonnell Douglas Alert Service Bulletin A27-250, Revision 3, dated May 15, 1991. This incorporation by reference was previously approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51, as of July 8, 1991 (56 FR 28479, June 21, 1991). Copies may be obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Business Unit Manager of TechnicalPublications - Technical Administrative Support, C1-L5B (54-60). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3229 East Spring Street, Long Beach, California 90806-2425; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, DC. \n\n\t(k)\tThis amendment becomes effective on July 23, 1992.