FLC OF AN LTT MADE A PRECAUTIONARY SHUTDOWN OF ONE ENG WHEN THERE WAS A DROP IN EGT AND FUEL FLOW; WITH AN ERRATIC TORQUE INDICATION; DURING CRUISE.

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AT FL160 IN CRUISE ALL WAS FINE. WE WERE IN CRUISE INDICATING 70 PERCENT TORQUE AND 100 PERCENT RPM WITH NORMAL EGT AND FUEL FLOWS. PICKING UP A TRACE OF RIME. THEN WE HEARD A SUDDEN CHANGE IN ENG SOUND AND WITNESSED AN INCREASE IN TORQUE ON THE R ENG TO 100 PERCENT; A DROP IN EGT; AND A DROP IN FUEL FLOW. WE COMPLETED THE EMER CHKLIST FOR ERRATIC TORQUE INDICATIONS. WHEN THE SRL AND TTL'S WERE TURNED OFF; THE ENG SURGED TO 120 PERCENT TORQUE. WE TURNED THE SRL'S AND TTL'S BACK ON; USED CONTINUOUS IGNITION; AND HAD ENG ICE ON. THE CHKLIST CALLED FOR ENG SHUTDOWN. THE ENG APPEARED TO BE RUNNING FINE WITH JUST SOME ABNORMAL INDICATIONS. WE CALLED MAINT AND THEY TOLD US TO PRESS ON AND CALL ON GND IN ALO. DURING MY DSCNT; I PULLED THE PWR LEVERS TO FLT IDLE. AT FLT IDLE; R ENG WAS PRODUCING 60 PERCENT TORQUE. WITH ALO RPTING VFR; WE WERE OVER THE ARPT AND OPTED TO SHUT DOWN THE R ENG. WE COMPLETED THE INFLT ENG SHUTDOWN CHKLIST. I ASKED FOR THE CRASH FIRE RESCUE EQUIP; AND THEN RELINQUISHED CTL OF THE ACFT TO THE CAPT FOR APCH AND LNDG. THE CAPT MADE A NORMAL LNDG WITH ONE ENG OUT USING ONLY FLAPS 20 DEGS AND 4 KTS ADDED TO VREF. UNLOADED AT GATE AS USUAL.