What was found
BURNING SMELL OBSERVED AFTER TAKEOFF DUMPED CABIN AND SMELL DISSIPATED A BIT. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. C/W FIM INITIAL EVALUATION PER TASK 21-20-00-810-012-A. FOUND NO DETECTED SMELL. BEFORE FLIGHT ENGINE COMPRESSOR WASH WAS DONE. C/W FIM TASK 21-20-00-810-009-A. GROUND RAN ENGINES ABOVE 65% N1 FOR 15 MINUTES. NO FURTHER ABNORMALITIES NOTED. A/C IS OK FOR CONTINUED SERVICE. ALSO C/W FORM M-749, INITIAL MILD ODOR NOTED IN CABIN. NO ODOR IN COCKPIT. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.