On February 27, 2019, about 1638 central standard time, a Warner Aerocraft Space Walker II airplane, N1778, was substantially damaged when it was involved in an accident near Devine, Texas. The pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the purpose of the flight was to overfly his private airstrip to evaluate the runway surface condition and to view wildlife. The pilot remembers an uneventful takeoff from Castroville Municipal Airport (CVB), Castroville, Texas, flying to his airstrip, and maneuvering near the north end of the airstrip as he prepared to make a low pass over the runway. The pilot does not recall the remaining portion of the flight besides a brief memory of the airplane descending toward trees in a 90° nose-down pitch attitude. The pilot does not recall if the airplane had any mechanical malfunctions during the flight. The pilot’s wife was in the kitchen when she heard her husband’s airplane overfly their residence a couple of times. She subsequently went outside and saw the airplane make a shallow turn to the north and estimated that it was higher than a nearby water tower. She noted that it was during this turn that she realized there was no engine sound coming from the airplane. The airplane then began a slow descent toward the tree line at the northern end of their property. She realized that the airplane had crashed when she saw a brief “puff of dust” among the trees. Based upon photographs of the accident site, there was tree damage preceding the grass runway. The airplane impacted the ground just beyond the trees resulting in substantial damage to the forward fuselage and left wing. A postaccident examination confirmed proper flight control continuity. A fluid consistent with aviation fuel was observed inside the fuel filter assembly. A visual examination of the engine crankcase did not reveal any holes, cracks, or oil leaks, and the engine crankshaft rotated smoothly with no binding. Internal engine and valve train continuity were confirmed, and compression and suction were observed on all cylinders while the crankshaft was rotated. The spark plugs were removed and exhibited features consistent with normal engine operation. Both magnetos provided spark on all leads when rotated with an electric drill motor. A partial disassembly of the engine did not reveal any evidence of mechanical failure with the cylinders, connecting rods or pistons, or their respective bearings. Adequate lubrication was observed throughout the engine and there was no evidence of oil starvation or excessive heat. The carburetor exhibited no evidence of malfunction when it was disassembled. The engine examination did not reveal any anomalies that would have precluded normal operation during the accident flight.