49-38-02: Bolt Replacement

49-38-02 DOUGLAS: Applies to All Models C-54 and DC-4 Aircraft. \n\n\tTo be accomplished at every 9,000 hours total airplane flight time. \n\n\tIn those cases where the present bolts have or will have accumulated more than 9,000 hours time prior to the next regular overhaul period, the first replacement time may be extended, at the discretion of the CAA Inspector, to coincide with a regular overhaul period but in no case should the adjustment time exceed 1,500 hours accumulated after January 26, 1948. Thereafter the bolt replacement shall be at the 9,000- or 18,000-hour period, whichever is applicable. \n\n\tReplace the following bolts: Fuselage to Center Wing Attachment; Outer Wing to Center Wing Attachment; Vertical Stabilizer Attachment to Fuselage Tail, Station 953; Engine Mount to Fire Wall Attachment; Horizontal Stabilizer to Fuselage Tail Assembly Attachment. \n\n\tThe 9,000-hour period may be extended to 18,000 hours when studs 4105725-1 and -2 in outer wing attachment have been replaced with special studs Nos. 4357723-1 and -2 having letter "R" stamped on thread end and bolts in all other attachments listed are replaced with NAS bolts with threads rolled after heat treatment. \n\n\tThe bolt part numbers and the number of bolts required are shown on pages 4 and 5 of the Douglas Service Magazine of August 1947. Bolts removed from the airplane are to be scrapped and are not to be used again. \n\n\t(Douglas Service Letter No. 66, Supplement No. 2, dated July 18, 1951, covers this same subject relative to wing alignment at Station 421.) \n\n\tThis supersedes AD 48-04-03.