What was found
(CAN) AIRCRAFT EXPERIENCED PROP OVERSPEED 1060 RPM, NR 1 PEC CAUTION LIGHT AND POWERPLANT MESSAGE. POWER LEVER RETARDED TOWARDS FLIGHT IDLE, NO EFFECT. ACC. QRH ENGINE FAIL / FIRE / SHUTDOWN COMPLETED ON LT (NR 1) ENGINE. MTCE CHECKED FAULT CODES IN CDS, FC 160-LOCAL NP MPU EXTRA PULSES, FC 999-NO DISPATCH -FC IN PEC. FSR OPENED LT HORSE COLLAR TO INSPECT DE-ICING BUSS TIES, FOUND ONE BUSS TIE SHEARED OFF BY CONTACT WITH MPU HOUSING AND EVIDENCE OF HEAT DAMAGE TO BUSS TIE AND PROPELLER BULKHEAD ( 30 MM), SHORTING WITH PROP DE-ICE ON. OPERATOR IS AWARE OF DH8-400-SL-61-002 AND DOWTY SL FOR FC 160. REPAIR TO PROPELLER BACKPLATE / BULKHEAD PERFORMED AS PER DOWTY CONCESSION LETTER.