48-02-05 DOUGLAS: Applies to DC-6 Serial Numbers 42854 Through 42880; 42882 Through 42884; 43000 and 43001. \n\nCompliance required by the first engine change after March 1, 1948. \n\nTo prevent the hot exhaust burning through the exhaust stack recess sheet on the upper and lower outboard accessory cowling, remove the present shield on the inboard side of the cowling and install a screw fastened exhaust chute of 0.042-thickness corrosion resistant steel sheet on the outboard side of the recess sheet. An air gap must exist between the exhaust chute and the recess sheet to allow a flow of ram air for heat dissipation. \n\n(Douglas Service Bulletin DC-6 No. 30 covers this same subject.)