47-42-02 DOUGLAS: (Was Mandatory Note 21 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. \n\nTo be accomplished as soon as possible but in any case not later than the first engine change after November 15, 1947. \n\nIt has been found that on some airplanes certain rework has been accomplished on the fire seal between the accessories section and the nacelle at the upper cowling former at the point where the carburetor airscoop skin rests on top of the firewall. This rework creates a hazardous condition by providing an opening from the accessories section into the nacelle, through the access hole under the non-ram air intake fairing. \n\nInspect all airplanes to ascertain that a fire seal is provided in this area. If the cowling fire seal has been cut away it must be replaced either with the original type seal or with a new type seal. \n\n(Douglas Service Bulletin DC-4 No. 19 covers a new type fire seal.)