What was found
SEVENTEEN MINUTES INTO THE FLIGHT, A FADEC FAIL 2 CAUTION ILLUMINATED. AT THAT TIME, THE #2 ENGINE TORQUE DECREASED FROM 58.8 TO 6.9, THEN INCREASED TO 19.9 WITHIN THREE SECONDS. THE #2 ENGINE TORQUE REMAINED AT 19.9 FOR THE REMAINDER OF THE FLIGHT. THE PILOT INITIATED A RETURN TO THE AIRPORT AT THAT POINT, RESULTING IN AN 18-MINUTE RETURN LEG. THIRTEEN MINUTES INTO THE RETURN, A FADEC MINOR EVENT WAS RECORDED. THE PILOT COMPLETED A RUN-ON LANDING. ALL PARAMETERS REMAINED WITHIN LIMITS DURING THE FLIGHT IN REFERENCE WITH THE EC135 FLIGHT MANUAL, SECTION 2.12 – ENGINE AND TRANSMISSION POWER LIMITS.