On November 22, 2021, about 1140 mountain standard time, an experimental amateur-built Vans RV-10 airplane, N54CT, was substantially damaged when it was involved in an accident near the Grassy Meadows/Sky Ranch Airport, Hurricane, Utah. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that prior to takeoff, he conducted an uneventful engine runup with the fuel selector set to the left fuel tank. Following completion of the engine runup, he switched to the right fuel tank and back taxied on runway 17 for takeoff. The pilot departed runway 17 with the intention of conducting a downwind departure to the north. While on the downwind leg, he reduced power and decreased his rate of climb due to rising engine operating temperatures. Shortly after, the engine had a complete loss of engine power. He advanced the propeller control to full rpm, switched the fuel selector valve to the left fuel tank, and turned on the fuel boost pump. Unable to restore engine power, he conducted a 360° turn to lose altitude prior to landing. However, after turning onto final approach for runway 17, he realized he did not have enough altitude to make it to the runway and initiated a forced landing to an open field. Subsequently, the airplane landed hard and impacted terrain before it came to rest in a nose low attitude. Postaccident examination of the airplane by the pilot revealed that the fuselage and left wing were substantially damaged. The wreckage was recovered to a secure location for further examination. Downloaded data from the airplane’s avionics recorded various engine parameters. The data showed that 1140:27-unit time, power was advanced for takeoff, with a fuel flow increasing to 22 gallons per hour (gph). About 51 seconds later, fuel flow started to decrease, however, fuel pressure remained around 26 psi. The data showed that when fuel flow decayed below 9.7 gph, engine rpm began to decrease from about 2,500 rpm. Examination of the recovered airframe and engine revealed that the fuel line from the fuel servo outlet port to the fuel flow transducer inlet port was loose at the fuel servo fitting. An external fuel source was attached to the left-wing fuel inlet line, and the No. 1 cylinder fuel injector line was removed from the fuel injector for testing. When power was applied to the airframe and the airframe boost pump was turned on with the throttle and mixture levers in the full forward position, fuel was observed expelling from the loose fuel line fitting, and no fuel was observed flowing from the fuel injector line. Additionally, damage sustained to the firewall appeared to restrict fuel flow from left- and right-wing fuel inlet lines. An external electric fuel boost pump was attached inline from an external fuel source to the fuel inlet line of the engine-driven fuel pump, and the loose fuel fitting at the fuel servo was tightened about 3.5 turns. The fuel boost pump was turned on with the throttle and mixture levers in the full forward position. Fuel was observed expelling from the cylinder no. 1 fuel injector line. Then the fuel outlet line at the fuel servo was loosened about 3.5 turns, fuel began to leak from the fitting, with no fuel expelling from the no. 1 fuel injector line.