Amateur-built Sonex accident near Malone, Florida, November 8, 2021

The NTSB's narrative final · quoted from the NTSB record

On the day of the accident, the pilot reported to a friend that the engine had lost power twice during a previous flight that day, but he informed another individual before departing on the accident flight that he had discovered what the problem was and would remain in the airport traffic pattern during the next flight. The pilot departed and proceeded north of the airport, where a witness near the accident site noted that the airplane flying in a westerly direction at high speed toward the ground. About 1 to 2 seconds after the airplane disappeared from his view, he saw black smoke. The airplane had impacted a tree adjacent to an abandoned runway while flying in a westerly direction, then impacted the ground and came to rest inverted. Postaccident examination of the wreckage revealed no evidence of preimpact failure or malfunction of the flight controls. Examination of the power train of the engine revealed no evidence of preimpact failure or malfunction. Although several of the spark plug gap measurements did not meet specification, these conditions likely existed when the flight departed and likely would not have resulted in a total loss of engine power. Extensive thermal damage to the engine precluded examination of the ignition and fuel metering system components. Therefore, it could not be determined whether there was a loss of engine power during the accident flight, or if the pilot was attempting to perform forced landing to the abandoned runway when the collision with the tree occurred.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.