89-08-10 McDONNELL DOUGLAS: Amendment 39-6185 as amended by Amendment 39-6236. \n\n\tApplicability: Model DC-9 and C-9 (Military) series airplanes, including Model DC-9-80 series airplanes and Model MD-88 airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo prevent structural failure of the empennage section, accomplish the following: \n\n\tA.\tFor airplanes equipped with dorsal fin two-piece attach angles, part numbers 5912188-27, -28, -29, and -30, accomplish the following: \n\n\t\t1.\tWithin 100 landings after May 17, 1982 (the effective date of Telegraphic AD T82-10-51-R1, later issued as Amendment 39-4481), visually inspect, from inside the airplane, the upper fuselage skin between longerons 4L through 4R for cracks in the area adjacent to the following fuselage stations appropriate to the model being inspected: \n\t\t\n\nSeries -10 and -20:\t\nFuselage Stations (FS) 901.400; \nSeries -30 and C9:\t \nFS 1080.400;\nSeries -40:\t\nFS 1156.400; \nSeries -50:\t\nFS 1251.400; and \nSeries -80:\t\nFS 1422.400. \n\t\n\t\t2.\tIf no cracks are found, accomplish the interim modification in accordance with McDonnell Douglas Service Sketch 3414, Revision D, dated May 11, 1982 (hereinafter referred to as 3414D), prior to the accumulation of 50 landings after June 7, 1982, for DC-9 and C-9 series aircraft, fuselage numbers 1 through 950; and prior to the accumulation of 400 landings from May 17, 1982, for all other affected airplanes. Verification that no cracks exist must be repeated immediately prior to accomplishment of the interim modification. The visual inspection required by paragraph A.1., above, must be repeated at intervals not to exceed 2,000 landings after the accomplishment of the interim modification. Prior to accumulating 4,000 landings from May 17, 1982, accomplish the modification specified in paragraph D.1., below. \n\n\t\t3.\tIf cracks are found, before further flight, accomplish the interim modification described in McDonnell Douglas Service Sketches 3413, Revision J, dated March 25, 1983 (hereinafter referred to as 3413J) and 3414D, and repeat the visual inspection required by paragraph A.1., above, thereafter at intervals not to exceed 2,000 landings. Prior to accumulating 4,000 landings from May 17, 1982, accomplish the modification specified in paragraph D.1., below. \n\n\tB.\tFor airplanes with dorsal fin one-piece attach angle, part number 5912188-5 or -6 accomplish the following: \n\n\t\t1.\tWithin 500 landings from May 17, 1982, for airplanes with less than 22,500 landings; and within 100 landings from May 17, 1982, for airplanes with 22,500 or more landings; conduct the visual inspections, from inside the airplane, in accordance with paragraph A.1., above. In addition, conduct a visual inspection of the dorsal fin attach angle, from the outside of the airplane, for cracks. \n\n\t\t2.\tIf no angle cracks are found, conduct an eddy current inspection of the angle in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A53-154, Revision 4, dated August 24, 1982; or conduct a dye penetrant inspection of the angle, within 1,000 additional landings, and thereafter at intervals not to exceed 3,000 landings, until the modification specified in paragraph D.1., below, is accomplished. \n\n\t\t3.\tIf skin cracks are found, before further flight, accomplish the modification described in McDonnell Douglas Service Sketch 3413J, and conduct eddy current inspections of the angle in accordance with paragraph B.2., above, thereafter at intervals not to exceed 3,000 landings, until the modification specified in paragraph D.1., below, is accomplished. \n\n\t\t4.\tIf dorsal fin attach angle cracks are found, accomplish the repair described in DC-9 Structural Repair Manual, Chapter 53-05, Figure 19, prior to the accumulation of 50 landings from June 7, 1982, for Model DC-9 and C-9 series airplanes, fuselage numbers 1 through 896; and prior to the accumulation of 400 landingsfrom May 17, 1982, for all other affected airplanes. Verification that no skin cracks exist must be repeated immediately prior to accomplishment of the repair. \n\n\t\t5.\tA dye penetrant or eddy current inspection of the angle in accordance with paragraph B.2., above, must be repeated at intervals not to exceed 3,000 landings after the accomplishment of the repair until the modification specified in paragraph D.1., below is accomplished. As an alternative to this procedure, accomplish the interim modification described in McDonnell Douglas Service Sketch 3414D, in accordance with the compliance schedule specified in paragraph B.4., above. The visual inspection required by paragraph B.1., above, must be repeated at intervals not to exceed 2,000 landings after the accomplishment of the interim modification. Prior to the accumulation of 4,000 landings from May 17, 1982, accomplish the modification specified in paragraph D.1., below. \n\n\tC.\tFor airplanes equipped with dorsal fin attach angle part number 5939711-1, -2, -501, -502, accomplish the following: \n\n\t\t1.\tPrior to the accumulation of 7,500 landings since installation of the above attach angle, or within 100 landings after August 19, 1988 (the effective date of telegraphic AD 88-17-51), whichever occurs later, unless previously accomplished within the last 2,000 landings, conduct a visual inspection of both angles, RH and LH, for cracks. \n\n\t\t 2.\tIf no angle cracks are found, conduct a visual inspection of the angle in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A53-223, dated November 30, 1988, (hereinafter referred to as ASB53-223), at intervals not to exceed 2,000 landings, until such time as the angles are replaced in accordance with paragraph D.1., below. \n\n\t\t3.\tIf dorsal fin attach angle cracks are found, before further flight, replace or modify cracked dorsal fin attach angle(s) in accordance with ASB53-223. \n\n\t\t4.\tIf skin cracks are found, before further flight, accomplish the modification in accordance with McDonnell Douglas Service Sketch 3413J. \n\n\tD.\tModification. \n\n\t\t1.\tReplacement or modification of the dorsal fin attach angle in accordance with ASB53-223, may be accomplished in lieu of the repetitive inspections required by paragraphs A., B., or C., above. \n\n\t\t2.\tUpon the accumulation of 30,000 landings after accomplishing the replacement or modification described in paragraph D.1., above, resume repetitive inspections in accordance with paragraph C., above, at intervals not to exceed 2,000 landings. \n\n\tE.\tAn alternate means 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, FAA, Northwest Mountain Region. \n\n\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may add comments and then send it to the Manager, Los Angeles Aircraft Certification Office. \n\n\tF.\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\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Director of Publications, C1-00 (54-60). These documents may be examined at FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or 3229 East Spring Street, Long Beach, California. \n\n\tThis AD supersedes two previously issued AD's: \n\n\t1.\tTelegraphic AD T82-10-51 issued May 5, 1982, as revised by Revision 1 dated May 17, 1982, Revision 2 dated June 7, 1982, and Revision 3 (Amendment 39-4481) which became effective on November 8, 1982. \n\n\t2.\tAirworthiness Directive 88-17-51 (Amendment 39-6016) which became effective on September 28, 1988, except tothose persons to whom it became immediately effective upon receipt of telegraphic AD T88-17-51 which was issued on August 19, 1988. \n\n\tAirworthiness Directive 89-08-10 (Amendment 39-6185) became effective on May 9, 1989. \n\n\tThis amendment (39-6236, a correction to AD 89-08-10) becomes effective on June 14, 1989.