On March 29, 2024, about 1250 eastern daylight time, a Navion B airplane, N5429K, was substantially damaged when it was involved in an accident near Sanford, Florida. The commercial pilot and one passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the preflight inspection, engine start, and taxi to runway 27R at Orlando Sanford International Airport (SFB), Sanford, Florida, were normal. Once cleared for takeoff, he advanced the throttle to full power and all engine indications were “green.” Shortly after takeoff, and after retracting the landing gear, “everything went silent” and the engine lost all power. The airplane descended back onto the runway, landed hard with the landing gear retracted, and skidded to a stop on the runway surface. The pilot and the passenger egressed the airplane and were met by first responders. A Federal Aviation Administration inspector responded to the accident site and examined the wreckage. Substantial damage was confirmed to the lower and aft fuselage. After recovery of the wreckage to the owner’s hangar, the engine was examined. The fuel tanks contained an adequate supply of fuel. The top spark plugs were removed and the engine’s crankshaft was turned manually using the propeller. Compression and suction were confirmed on all cylinders. The cylinder interiors were examined with a lighted borescope; no anomalies were found with the piston heads, valves, or cylinder walls. The electric fuel pump was energized and pumped normally. The engine-driven fuel pump was normal in appearance. The right magneto was turned and produced spark on all towers. The left magneto could not be tested. No preimpact mechanical deficiencies were noted that would have precluded normal operation of the engine and airframe.