CEN23LA114

The flight instructor stated that while practicing power off stalls the student pilot added engine power and was retracting the wing flaps when the engine began to lose power. The instructor took control of the airplane and scanned the engine instruments. He noted that oil temperature was in the green range and the oil pressure was 0 psi and blinking in the red. The engine lost total power and the flight instructor performed a forced landing to a field. During the landing roll out, the airplane nosed over and came to rest inverted. Substantial damage was sustained to the empennage and vertical stabilizer. An examination of the airframe and an engine run did not detect any preimpact anomalies that would have contributed to a loss of engine power. The airplane was operating in conditions conducive to the formation of carburetor icing at glide and cruise power and serious icing at glide power. The instructor reported the use of carburetor heat during the flight training. The reason for the loss of engine power could not be determined with the available information.

On February 18, 2023, about 1100 central standard time, a Cessna 150L airplane, N6536G, was substantially damaged when it was involved in an accident near Venus, Texas. The flight instructor and student pilot were not injured. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as an instructional flight. The flight instructor stated that while practicing power off stall recoveries, the student pilot had added engine power and was retracting the wing flaps when the engine began to lose power. The instructor took control of the airplane and scanned the engine instruments. He noted that oil temperature was in the green range and the oil pressure was 0 psi and blinking in the red. The engine lost total power and the flight instructor performed a forced landing to a field. During the landing roll out, the airplane nosed over and came to rest inverted. Substantial damage was sustained to the empennage and vertical stabilizer. The airplane was recovered back to the flight school. An investigator from the National Transportation Safety Board traveled to the flight school and examined the airframe and engine. No preimpact anomalies were noted. The engine remained attached to the airframe and the investigator started the engine normally and idled the engine at 900 rpm for several minutes. Oil pressure was indicating in the normal operating range. The power was then advanced to 1,300 rpm with no discrepancies observed. Due to safety concerns, the engine power was not advanced further. When the investigator actuated the carburetor heat control, there was a drop in engine speed as expected. A magneto check was performed without any deficiencies noted. A review of the Carburetor Icing Probability Chart located in the Federal Aviation Administration’s Special Airworthiness Information Bulletin CE-09-35, Carburetor Icing Prevention, dated June 30, 2009, found that the airplane was operating in conditions conducive to the formation of carburetor icing at glide and cruise power and serious icing at glider power. The instructor reported the use of carburetor heat during the stall training.