What was found
THE PILOT HAD JUST COMPLETED A FLIGHT & LANDED AT RECEIVING HOSPITAL, NORMAL SHUTDOWN & UNLOADED PATIENT. THE PILOT THEN POWERED UP THE ACFT TO CRANK FOR THE RETURN FLIGHT TO BASE & WHEN BATTERY POWER WAS APPLIED NOTICED THAT THE ENG FIRE LIGHT WAS ILLUMINATED. CHECKED ENG TEMP & OPENED ENG COWL. TOOK ACFT OOS & CALLED MECHANIC ON CALL. THE PILOT THEN APPLIED BATTERY POWER AGAIN TO CHECK CYCLES WITH NO FIRE LIGHT INDICATED. MECHANIC ARRIVED & ENGAGED ACFT BATTERY SWITCH WITH NO ENG FIRE INDICATION NOTED. INSPECTED ENG FIRE DETECTORS & WIRING, NO DEFECTS NOTED. POWERED UP ACFT BATTERY AGAIN, CHECKED ENG FIRE SYS IAW FLM, NO DEFECTS NOTED. GND RUN ACFT & SHUTDOWN WITH NO DEFECTS NOTED. ACFT RTS.