Narrative:

During initial takeoff on a dual training flight; the engine began to run roughly (intermittent cut-out of power) at about 400 ft AGL. I immediately took control of the aircraft and declared an emergency. I ran through my emergency flow and since the engine was still producing power; I opted to enter the crosswind for the runway I just departed. ATC cleared the area and I stated to them that my engine was running roughly and needed to land. While on downwind; I requested runway xx for a quicker landing and was granted it. I landed and taxied off under the aircraft's own power. Engine no longer continued to run roughly. Prior to shutdown; I thoroughly checked fuel pumps; fuel selectors; mixture; etc; and no indications of an abnormal function were evident. During run-up prior to takeoff; magneto check was within standards.

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Original NASA ASRS Text

Title: ROUGH RUNNING ENGINE PROVOKES EMERGENCY DECLARATION AND RETURN TO LAND FOR INSTRUCTOR AND STUDENT PLTS ABOARD A PA28.

Narrative: DURING INITIAL TKOF ON A DUAL TRAINING FLT; THE ENG BEGAN TO RUN ROUGHLY (INTERMITTENT CUT-OUT OF PWR) AT ABOUT 400 FT AGL. I IMMEDIATELY TOOK CTL OF THE ACFT AND DECLARED AN EMER. I RAN THROUGH MY EMER FLOW AND SINCE THE ENG WAS STILL PRODUCING PWR; I OPTED TO ENTER THE XWIND FOR THE RWY I JUST DEPARTED. ATC CLRED THE AREA AND I STATED TO THEM THAT MY ENG WAS RUNNING ROUGHLY AND NEEDED TO LAND. WHILE ON DOWNWIND; I REQUESTED RWY XX FOR A QUICKER LNDG AND WAS GRANTED IT. I LANDED AND TAXIED OFF UNDER THE ACFT'S OWN PWR. ENG NO LONGER CONTINUED TO RUN ROUGHLY. PRIOR TO SHUTDOWN; I THOROUGHLY CHKED FUEL PUMPS; FUEL SELECTORS; MIXTURE; ETC; AND NO INDICATIONS OF AN ABNORMAL FUNCTION WERE EVIDENT. DURING RUN-UP PRIOR TO TKOF; MAGNETO CHK WAS WITHIN STANDARDS.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.