49-06-02\tDOUGLAS: Applies to DC-6 Aircraft. \n\n\tTo be accomplished at every 8,000 hours of total flight time.\n \n\tReplace the following attachment bolts: (1) fuselage to center wing, (2) outer wing to center wing, (3) vertical stabilizer to fuselage, (4) horizontal stabilizer to fuselage and, (5) engine mount to firewall. The 8,000-hour period may be extended to 16,000 hours when studs 2325933 or 2340697, 2353832, 4329243 and 4333164 are replaced with studs 2361992, 2361993, 4361995 and 4361994, respectively, having letter "R" stamped on thread end and bolts in all other attachments listed are placed with NAS bolts with threads rolled after heat treatment. Bolts and studs removed from the airplane are to be scrapped and are not to be used again. \n\n\t(Douglas Service Bulletin DC-6 No. 410 contains a list of all studs and bolts affected and their replacements.)