Date: 201206
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Cessna 150
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Takeoff / Launch
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Engine
Component problem: Improperly Operated
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Confusion; Training / Qualification
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Departure Airport; General Declared Emergency
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: I was on a solo training flight practicing my Commercial maneuvers. When I returned to the airport; I had enough time for some touch-and-go's. After two go-arounds; I landed the Cessna 150; pushed in the carb heat to turn it off and advanced the throttle to take off and enter the pattern one last time. On climb out; maybe around 300 FT AGL; I felt and heard something wrong with the airplane. She wasn't climbing anymore; and the engine seemed to have an oscillating sound to it instead of the usual full-power drone heard during take-offs. I immediately requested [return to a runway]. It would have been easier to enter left downwind of that runway's pattern and land. ATC gave it to me; but then the airplane felt like it may have been dropping; the engine sounded worse; and I had a sort of gut feeling that if the plane wasn't on the ground soon; I wouldn't be landing on a runway. I told Tower I was declaring an emergency and was going to take [the nearest runway] (winds were calm that morning). There was no other traffic in the area; and I knew I wouldn't be fighting a tailwind. I pulled the 180; configured for landing; and idled the engine from take-off power and pulled on carb heat to make the landing. After landing; I taxied off the runway and cleaned up the airplane. The airplane sounded just fine again as I taxied back to parking. During the emergency; I checked my instruments: RPM's were normal; suction was fine; there was plenty of fuel; and oil temp and pressure were in the green arcs. When I got back to the flight school; I debriefed with the Chief CFI. He seemed to think that my problem was the mixture. I had pushed it full rich for that touch-and-go; despite having it leaned for my maneuvers and other two laps in the pattern. I had not taken into consideration that the temperatures were warming; as they had been cool earlier during the beginning of my maneuvers practice. With approximately 25 hours in the C-150 and little experience with it during summer operations; I was unaware of the adverse affects having the mixture too rich would have on this particular aircraft. Now armed with more knowledge about the C-150's engine and tendencies; I will be sure to pay more attention to the mixture to prevent further [problems].




Synopsis: C150 pilot reported power loss in pattern; declared an emergency; returned for an immediate landing. FBO opinion was that he mis-set the mixture; running full rich when he should have leaned a bit.