TRAINING FLC OF A SMA TWIN ENG ACFT EXPERIENCED A PWR REDUCTION SURGE ON ONE ENG DURING INITIAL CLB AFTER TKOF AND RETURNED TO LAND.

Narrative

PREFLT AND TAXIED TO RWY 7 FOR TRAINING FLT IN THE N PRACTICE AREA. PERFORMED ENG RUN-UP; EVERYTHING NORMAL. CLRED FOR TKOF; TOOK ACTIVE RWY; ADVANCE THROTTLES. EVERYTHING WAS IN THE GREEN; OIL PRESSURE; TEMP; FUEL PRESSURE; AND AIRSPD WAS ALIVE. ABOUT MIDWAY DOWN THE RWY; AT ABOUT 200 FT; THE L ENG BEGAN TO SURGE. NOTICED NO DROP IN RPM AND MP. AT THIS POINT; COMMITTED TO GO. BROUGHT GEAR UP; MAINTAINED AT LEAST BLUE LINE AND DIRECTIONAL CTL AND CONTINUED. WHEN THE ENG BEGAN TO SURGE; STUDENT RELEASED CTRL OF AIRPLANE TO ME (THE INSTRUCTOR). ASSIGNED THE STUDENT THE TASK OF COMS. ENTERED A R DOWNWIND FOR RWY 7 AND CLBED TO 1200 MSL. UPON LEVEL OFF; THE ENG STOPPED SURGING. TURNED BASE; REDUCED THROTTLE; GEAR DOWN AND LANDED ON RWY 7 WITHOUT A PROB. THE TWR HAD SENT THE RESCUE EQUIP TO THE RWY. DO NOT REMEMBER ENG SURGING FROM BASE FINAL AND TAXI. THE STUDENT SHOULD HAVE CONTINUED TO FLY THE AIRPLANE; BUT I; THE INSTRUCTOR HAD NO CTRL OVER HIS ACTIONS. I DID NOT HAVE TIME TO DO OTHERWISE. I HAD TO FLY OR RISK SOMETHING UNFORTUNATE. THE ACFT IS A PA23-160. AS OF THIS TIME; THE MECHS ARE NOT SURE WHAT THE PROB WAS.