Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness; Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Flight Crew Diverted; Flight Crew Landed As Precaution; Flight Crew Landed in Emergency Condition
Aircraft
On the way to ZZZ airport to get fuel the engine started to stutter. I immediately pulled carb heat; verified mixture full rich; and fuel selector on; fuel gauge showing to have fuel; oil pressure and temperature both in the green. I continually pumped the throttle; as that seemed to be the only thing to keep the engine running partially. I looked for the private grass strips that I know of in the area; I was too far and too low to make it to them so I continued toward the best field options I could see when I remembered a friend of my boss had a big field he said we could land at just north of ZZZ. I then located the field and proceeded to circle the field while performing my final check list. I secured the engine and preformed a textbook 3 point soft field landing. I called my boss and he promptly arrived with an aircraft mechanic to inspect the airplane. They found absolutely no evidence of a problem so they started the airplane and my boss flew it back to the airport where he could have it checked tested and fixed. No one was injured; no damage to persons or property occurred; and the airplane was in perfect flying condition. The airplane is now grounded until the issue can be found; however; my boss could not duplicate the issue and the engine ran perfectly smooth on the way back to the airport. The only thing they could come up with to this point is carb ice or vapor lock. Those are just guesses seeing how the issue cannot be duplicated. Also; I used carb heat and it only seemed to escalate the issue; progressively losing power and never restoring fuel flow. When pumping the throttle the engine would start back up for about a second per pump. This continued for about 2 minutes before it stopped healing and the engine stopped completely.
The reporter stated that the field where he made the emergency landing was a field that they used for practicing soft field landing. He added that Maintenance has replaced the fuel line precautionary and ensured that the carb heat was working properly. They were unable to determine the actual cause of the engine shutting down; but suspect icing was the probable cause since the aircraft has been operating normally since the incident.
Aeronca Pilot reported landing in an open field due to a loss of engine power.