What was found
DEPARTING PANC. WHILE PASSING THRU FL310 THE LH ENG FIRE LIGHT ILLUMINATED. PILOT DECLARED AN EMERGENCY AND RETURNED TO THE AIRPORT. NO INDICATIONS OUTSIDE OF THE WARNING LIGHT WERE PRESENT REGARDING ANY FIRE. LANDING WAS UNEVENTFUL AND AIRCRAFT RETURNED TO THE HANGAR. INITIAL INSPECTION POINTS TO A FALSE WARNING. INSPECTION OF THE INDIVIDUAL PHOTOVOLTAIC SENSORS AND WIRING SHOW NOT FAULTS. THIS IS A KNOWN ISSUE WITH THE PHOTOVOLTAIC SENSOR SYSTEM WHEN SUNLIGHT PASSES THROUGH THE EXHAUST GAPS IN THE COWLING AND HITS THE SENSORS AT JUST THE RIGHT ANGLE. WORKING ON CONFIRMING THIS NOW. NO EVIDENCE OF ANY HEAT OR FIRE IN THE COWLING.