47-51-16 DOUGLAS: Applies to DC-6 Serial Numbers 42854 Through 42880, Inclusive; 42882 Through 42891, Inclusive; and 43000 Through 43009, Inclusive; 43055; and 43056. \n\nTo be accomplished not later than August 1, 1948. \n\nIn order to increase the strength of the flap support assembly at wing Station 378 and to replace the temporary rework outlined in Douglas Co. Service Letter of May 12, 1947, which was necessitated by failure of the flap hinge support assembly on an airplane in flight, the following must be accomplished: \n\n(a)\tRemove the two Shafer bearings, P/N AB-4A from flap link assembly, P/N 4325008 and press in new Shafer bearings, P/N AB-5A and stake in place. \n\n(b)\tRemove outboard flap link support assembly, P/N 5107188, and line ream (0.312-0.313) diameter through to permit use of 5/16-inch bolt for attachment of upper end of link assembly, P/N 4325008. Assembly, P/N 5107188 becomes P/N 5107188-500 after rework. \n\n(c)\tPress out old bushing, P/N 1338719, two places in flap hinge bracket assembly, P/N 3320998, and press in new bushings, P/N 1338719-500. \n\n(d)\tAfter replacing P/N 5107188-500 replace P/N 4325008, using bolts, P/N 2356375-22; washers, P/N 124682-5-12-6 and P/N AN 960-516; nut, P/N AN 310-5 and cotter pin, P/N AN 380-2-3. \n\n(Douglas Service Bulletin DC-6 No. 66 covers this same rework.)