48-07-03\tDOUGLAS: Applies to DC-6 Serial Numbers 42854 Through 42896; 43000 Through 43024; 43035 through 43053; 43055 Through 43064; 43103 Through 43119; 43129 and 43132 (Note: Some of the Above Airplanes May Have Had Part of the Changes Installed Before Delivery From the Factory.) \n\n\tCompliance required by September 15, 1948. \n\n\tTo provide safer and more satisfactory operation of all the doors, the following reworks must be accomplished: \n\n\t(1)\tInstall new latch bolts on all emergency exit doors, main passenger door, crew door, heater compartment door, and belly cargo compartment doors, to incorporate a notch which allows slow depressurization before the door can be fully opened in the event the handles are inadvertently turned toward the "OPEN" position while the cabin is pressurized. \n\n\t(2)\tRework the operating and locking mechanisms of the passenger, crew, and emergency exit doors, to increase their strength and prevent malfunctioning. \n\n\t(3)\tInstall visual inspectionplugs in the passenger, crew, and emergency exit doors to allow individual inspection of each lock bolt to determine if it is properly locked. \n\n\t(4)\tInstall an assist handle above the main cabin door handle to prevent accidental grabbing of the inside door handle. (NOTE: Even in cases where the door handles have been changed so that the handle points downward when the door is closed and locked, it will still be necessary to install the assist handles.)