On May 16, 2018, about 1400 mountain daylight time, a Zenith 701 airplane, N44CP, was substantially damaged when it was involved in an accident near Jackson, Wyoming. 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 he had just finished rebuilding the airplane and that the accident flight was the first flight since an accident about 5 years earlier. While returning to land on a grass strip and shortly after switching from the right to the left fuel tank, the engine began to run roughly and “sputter.” The pilot reported that he did not attempt to switch back to the right tank because the airplane to too low and he was “just trying to get to the runway.” He added that the airplane was “high and fast” on the approach but that he chose to continue the landing due to the engine problem. Upon landing, the airplane bounced, the nosewheel hit the ground hard and collapsed, and the airplane then nosed over and came to rest inverted. Postaccident engine examination revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. The pilot reported that the airplane had an adequate amount of fuel onboard at the time of the accident. He added that a fuel quick disconnect from the left wing fuel tank was loose before the flight, so he reconnected the fitting and speculated that air might have entered the fuel lines when he reconnected it or that the fuel may have been “bad” because the airplane had been sitting for 5 years.