What was found
BAD ODOR & SMOKE OCCURRED IN THE CABIN AFTER TAKEOFF. RETURNED TO FIELD. FOLLOWED TASK 05-51-26-800-801C1. ISOLATED SMELL TO RT PACK, NO TRACE OF OIL IN RT DUCTS. RAN ENGS AT 65% - 70% POWER. UNABLE TO REMOVE SMELL FROM RT PACK. 40 MIN ENG RUN & NO SMOKE IN CABIN WITH LT OR RT PACK IAW AMM 05-51-26-800-801C1. REPLACED BOTH RECIRC FILTERS IAW EF AMM 21-25-01. PERFORMED BURN OUT WITH BOTH ENGS RUNNING ABOVE IDLE & ACFT SYSTEMS ON WITH NO TRACES OF ANY SMOKE OR ODOR.