Accident Details
On July 4, 2009, at approximately 1045 eastern daylight time, a Cessna 172M, registration N64178, collided with the ground during an emergency landing in Princeton, New Jersey. The solo instructional flight was conducted under 14 Code of Federal Regulations Part 91, with no flight plan filed. The flight had originated shortly before the accident in visual meteorological conditions. The student pilot was not injured, and the airplane sustained substantial damage.
Pilot Actions
The student pilot reported preparing for a touch-and-go landing in the traffic pattern. After a normal preflight inspection and engine run-up, the pilot taxied to the active runway and departed to remain in the closed traffic pattern. As the airplane climbed, the pilot turned crosswind, downwind, and completed the landing checklist. While turning to base and reducing engine power, the engine went to idle. The pilot immediately applied full power but received no engine response. The power briefly returned as the pilot turned toward the runway, then decreased again, prompting an emergency landing in a field. The student pilot noted that the carburetor heat check prior to takeoff indicated a normal drop in rpm, and that carburetor heat was in use when the engine lost power.
Aircraft Examination
An FAA inspector examined the accident site, where the airplane had descended through trees into a field. Inspection of the airframe and flight control systems revealed no evidence of preimpact mechanical malfunction. The fuel system was intact: both fuel tanks were full, the fuel selector was in the "both" position, and no water or debris was found. A cursory examination of the engine and its components also revealed no preimpact mechanical malfunction.
Environmental Conditions
At the time of the accident, the ambient temperature was 75 degrees Fahrenheit, with a dew point of 55 degrees Fahrenheit. Review of the carburetor icing probability chart indicated that serious icing could occur at glide power.