50-16-01 DOUGLAS: Applies to All Model DC-6 Airplanes Below Serial Number 43149. \n\n\tCompliance required as soon as possible but in any event not later than January 1, 1951. \n\n\t1.\tConduct electrical and mechanical functional check of propeller reverse mechanism, throttle system. \n\n\t2.\t(a)\tRework fish mouth in the 2345735 throttle latch assembly to assure a more positive lock. \n\n\t\t(b)\tRotate the 2333338 arm-throttle reverse 20 degrees clockwise on the shaft of the 4333339 lock assembly or replace with new 2333338 "F" change parts. \n\n\t(Douglas General Service Letters DC-6 No. 19, dated November 18, 1949, and DC-6 No. 23, dated January 20, 1950, cover the above two items.)