What was found
DEPARTING TUCSON, DURING CLIMBOUT, NW BOUND, COPILOT ANNOUNCED "MASTER WARN - RT ENG FIRE". NO OBVIOUS INDICATION OF A FIRE. REQUESTED A CHANGE OF COURSE DUE TO THE FIRE DETECTION SYS DESIGN - PHOTO-SENSITIVE. AFTER FLYING THE NEW HEADING FOR APPROX 3 MIN, THE ANNUNCIATORS REMAINED ON, DIVERT TO TUCSON, TO HAVE A MECHANIC INVESTIGATE. DECLARED AN EMERGENCY, LIGHT HAD BEEN ON FOR 3 MINUTES, AND FLYING A NEW HEADING. DURING THE DESCENT AND VECTOR TO 29R, THE R ENG FIRE LIGHT FLICKERED, THEN EXTINGUISHED, APPROX 5 MIN PRIOR TO LANDING. AN UNEVENTFUL LANDING WAS MADE. TECHNICIAN WAS DISPATCH TO LOCATION TO INVESTIGATE. THE ‘ENGINE FIRE` INDICATION WAS A FAULTY INDICATION AND THE AC WAS CLEARED AND RETURNED TO SERVICE TO FLY BACK TO SNA (2-21-08) WITH NO FURTHER INCIDENT. THE FLIGHT BACK TO SNA WAS NOT CARRYING ANY PAX.