What was found
FLIGHT CREW NOTICED AN ACRID SMELL IN THE CABIN AREA RESEMBLING BURNING RUBBER / PLASTIC. NO VISIBLE CUES NOTED. ALL FLIGHT AND ENGINE GAGES NORMAL. OPENED UP AREAS INSIDE THE UPPER AFT HELL HOLE AREA AND INSPECTED, ALSO CHECKED THE ENGINE BAY FOR AIR CONDITIONING BELT, BELT IS IN GOOD CONDITION, NO SMELLS UP IN THE AFT AREA AND GROUND RUN WITH A/C OFF AND ON, NO SMELLS PRESENT AT THIS TIME. ALL PANELS REINSTALLED AND SECURED. AIRCRAFT IS APPROVED FOR RETURN TO SERVICE AT THIS TIME FOR THE INSPECTION COMPLETED.