Piper J3C-65 N88313 accident near Seguin, Texas

Probable cause

The partial loss of engine power for reasons that could not be undetermined because an examination of the engine did not reveal any malfunctions or failures that would preclude normal operation.

NTSB analysis

The flight instructor and student pilot planned on departing from a private grass airfield and fly to another airfield, in order to refuel the airplane before practicing landings. The instructor reported that the airplane had 3 gallons of fuel onboard. Shortly after takeoff, when the airplane was about 200 feet in the air, the flight instructor realized engine power was decreasing. The instructor reported that the throttle was already at full power and with obstacles ahead, he elected to turn back to the departure runway. The instructor made a 150-degree turn, but was unable to recover from the turn, and the left wing impacted terrain. The instructor added that the engine may have had carburetor icing, though he did not apply carburetor heat. An automated weather station located about 13 miles west of the accident site, reported, temperature 72 degrees F, and a dew point of 36 degrees F. A review of the carburetor icing probability chart, indicated that the airplane was operating in an area that was associated with a risk of carburetor ice formation, at glide and cruise power. A visual examination of the airplane revealed that the carburetor and gascolator were broken off during the impact, and the fuel tank was empty. No malfunctions or failures were noted that would have precluded normal operation. A reason for the loss of power was not determined.

Text from the NTSB. Open the NTSB docket for CEN13LA193 for the full record.