What was found
FLAP FAIL CREW WAS STAGED TO LANDED ON FINAL. CONDITIONS WERE IMC, ENGINE AI AND WING STAB WAS ON. UPON SWITCHING FROM FLAPS 0 TO 1, FLAP FAIL CAS MESSAGE IMMEDIATELY APPEARED. CREW REQUESTED PUBLISHED MISSED APPROACH. CREW RAN FLAP FAIL MESSAGE AND NO CHANGES TO THE FAILURE APPEARED. CREW DIVERTED TO KSYR. NO VISIBLE DAMAGE WAS SEEN ON FLAP SURFACES UPON POST F LIGHT INSPECTION. AOG MAINTENANCE CREW COULD NOT DUPLICATE THE PROBLEM AFTER SEVERAL FLAP OPERATIONAL CHACKS. AOG CREW SWAPPED FCE 1 & 2 AND RE-RIGGED THE FLAPS AND SPOILERS. AIRCRAFT WAS RETURNED TO SERVICE.