AN ATR72 ON INITIAL CLB DECLARED AN EMER AND RETURNED TO THE DEP FIELD DUE TO R ENG FLUCTUATING TORQUE -20% TO +30%.

Narrative

FLT HAD TO RETURN DUE TO EXTREME TORQUE FLUCTUATIONS BY ENG #2 DURING CLBOUT. AS WE WERE ASSIGNED TO POSITION AND HOLD; ACFT ON RWY 27; THE #2 ENG; BY ITS SOUND; COULD BE HEARD HAVING SOME TYPE OF SMALL AND QUICK FLUCTUATIONS. THE CAPT AND I IMMEDIATELY LOOKED AT THE ENG GAUGES; AND THEY INDICATED TO BE ALL IN THE GREEN. WE CONFER; AND CONCLUDED THAT IT WAS PROBABLY JUST A SMALL GLITCH BY THE ENG; AND IT WAS NOTHING OUT OF THE ORDINARY; AND WERE STILL GOOD TO GO. WE PROCEEDED WITH THE BEFORE TKOF CHKLIST; WHICH WAS FOLLOWED BY THE TKOF ROLL. AFTER V1; VR; ENG #2 HAD A DRASTIC REDUCED IN TORQUE (AT LEAST 40%); AND WAS FOLLOWED BY THE ENG TRYING TO FEATHER. THE ENG SEEMED TO REGAIN PWR AND ACT NORMAL FOR THE NEXT FEW SECONDS. AT THIS POINT WE REQUESTED VECTORS BACK TO THE ARPT. DURING THE CLB; THE ENG CONTINUED TO FLUCTUATE (-20% TO 30% TORQUE). AT THIS POINT WE DECLARED AN EMER. WE KEPT THE ENG #2 ON LINE; AS IT WAS STILL PRODUCING SOME KIND OF PWR; AND WE WERE ALREADY IN THE LNDG PATTERN. WE PERFORMED THE VISUAL APCH AND LANDED WITH NO FURTHER INCIDENT. MAINT WAS CALLED OUT; AND ALL THE PAX WERE DEPLANED.