What was found
WHILE AT 2000' MSL ENROUTE AT 2200EDT BETWEEN KPYM (BASE OF OPERATIONS) AND FALMOUTH HOSPITAL, MASSACHUSETTS WITH A NURSE AND PARAMEDIC ONBOARD, TO PICKUP A PATIENT AT FALMOUTH HOSPITAL, DETECTED A FUEL FUME ODOR FROM AIRCRAFT ENVIRONMENTAL CONTROL SYSTEM (ECS) VENTILATION. SECURED ECS VENTILATION SYSTEM AND THEN BRIEFLY CRACKED OPENED SLIDING WINDOWS ON COCKPIT DOORS AND CABIN DOORS TO QUICKLY AND THOROUGHLY ELIMINATE SMELL. ABORTED THE MEDICAL TRANSPORT MISSION, DETERMINED SAFE LANDING CRITERIA, AND COMPLETED AN UNEVENTFUL SHORT FLIGHT BACK TO KPYM (BASE OF OPERATIONS).