Incident Overview
A student pilot on a local instructional flight experienced an engine anomaly shortly after takeoff. According to the student pilot, she had just landed from a previous instructional flight and received a solo endorsement from her instructor while taxiing back to the departure end of runway 28. She then taxied onto runway 28 for departure, applied full throttle, and the airplane lifted off normally.
Engine Roughness and Actions Taken
At approximately 500 feet above ground level, the engine began to run rough and the RPM dropped to 1900. In response, the student pilot immediately lowered the airplane's nose to achieve best glide speed and initiated a left turn to return to the airport, aiming to land on runway 10. About 20 seconds after the engine roughness began, she applied carburetor heat and then reduced the throttle to idle. She did not subsequently increase power after carburetor heat application, and the throttle remained idle for the remainder of the approach.
Landing and Outcome
As the airplane descended over midfield, the pilot applied full flaps. The airplane overflew the runway and touched down in the grass immediately off the departure end of runway 10. It then struck a fence and nosed over.
Post-Accident Examination
A post-accident examination of the airplane and engine found no evidence of mechanical failure or malfunction. The engine was started and operated without any signs of failure. Additionally, a review of carburetor icing probability charts indicated that the aircraft was operating in conditions not conducive to carburetor icing at the time of the accident.
Pilot Experience
The student pilot had accumulated 43 total flight hours at the time of the incident.