Flight and Incident Overview
A flight instructor and a private pilot were conducting a local training flight. The preflight inspection, engine start, and run-up were reported as normal. The private pilot then taxied the airplane to runway 19 and performed a soft field takeoff. The pilot rotated the airplane at 65 MPH. Before reaching 80 MPH, the engine lost power. The private pilot applied carburetor heat, but it had no effect. The flight instructor then took over the controls and landed the airplane straight ahead on a grass lawn.
Post-Accident Examination
Examination of the airplane revealed no preimpact failure of the engine or airframe. A postaccident engine run was completed satisfactorily. However, moisture was found in the engine air inlet system, specifically between the air filter and the carburetor air box. The airplane had been kept outside after its last flight, where it had been exposed to a wind-blown snow storm and a driving rain storm. At the time of the accident, the outside air temperature was below freezing.
Conclusion
The investigation did not establish a specific cause for the engine power loss. The presence of moisture in the air intake system was noted, but no explicit causal link was determined.