72-25-03 BOEING: Amdt. 39-1560 as amended by Amendment 39-1575 is further amended by Amendment 39-1596. Applies to main landing gear beams made from 7079-T6 material on all Model 727 Series Airplanes certificated in all categories. \n\tCompliance required as indicated: \n\tTo detect cracks in the main landing gear trunnion support beam, accomplish the following: \n\t(a)\tInspect all beams in accordance with (c) below within 600 hours time in service or 90 days from the effective date of this AD, whichever occurs first, and at intervals thereafter not to exceed 600 hours time in service or 90 days, whichever occurs first. \n\t(b)\tInspect all beams in accordance with (d) below within 1200 hours time service or 180 days, whichever occurs first, except parts nos. 65-16230-23, -24, -25 and -26, and those beams sleeved in accordance with Boeing Service Bulletin No. 57-122 dated October 15, 1971, or later FAA approved revisions. \n\t(c)\tUltrasonically inspect the bearing bore in accordance with Boeing Service Bulletin No. 57-119, Revision 2, dated 14 November 1972 or later FAA approved revision, or an equivalent inspection approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. \n\t(d)\tEddy-current inspect inside the trunnion bore in accordance with Boeing nondestructive test document No. D6-7170, Part 6, 57-10-27 Figure 1, or an equivalent inspection approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. Reinstall the bearing in accordance with Boeing Service Bulletin No. 57-120, Revision 1, dated 9 July 1971 or later FAA approved revisions. \n\t(e)\tAny beam in which evidence of a crack in the bearing bore is found must, prior to further flight, be replaced with a beam inspected per this AD and found to be uncracked, or reworked in accordance with instructions in Boeing Service Bulletin No. 57-120, Revision 1, dated 9 July 1971 or later FAA approved revisions, or in accordance with instructions approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. \n\t(f)\t(1)\tLanding gear beams, part numbers 65-16230-23, -24, -25 and -26, and those beams sleeved in accordance with Boeing Service Bulletin No. 57-122 dated 15 October 1971 or later FAA approved revisions, must be replaced with the redesigned beam (P/N 65-62335) no later than 1 July 1974. \n\t\t(2)\tAll other beams must be replaced with the redesigned beam (P/N 65-62335) no later than 1 January 1974. \n\t(g)\tAirplanes having cracked landing gear beams which require replacement under this AD may be flown in accordance with FAR 21.197 to a base where the replacement of parts can be accomplished. \n\t(h)\tAs an alternative to the inspection required in paragraph (b) above, those beams which will be replaced prior to July 1, 1973 need not be inspected in accordance with paragraph (d) above. Those beams allowed to remain in service beyond the time intervals specified in paragraph (b) must be replaced by July 1, 1973. Operators must assurethemselves of parts availability prior to electing this alternative.\n\tThis supersedes Amendment 39-1162 as amended by 39-1306 (AD 71-5-4). \n\tAmendment 39-1560 became effective upon publication in the Federal Register for all persons except those to whom it was made effective immediately by telegram dated 10 November 1972. \n\tAmendment 39-1575 became effective 26 December 1972. \n\tThis Amendment 39-1596 becomes effective March 2, 1973.