BROWN BENJAMIN C CHALLENGER II

Full Narrative

On September 1, 2023, at 0910 eastern daylight time, an experimental amateur-built Challenger II, N2480Y, was substantially damaged when it was involved in an accident near Moultonborough, New Hampshire. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
According to the pilot, during takeoff and initial climb, the engine was producing full power without anomalies. Then, while still in the climb, the engine gradually sustained a total loss of power. The pilot attempted to make two engine restarts but was unsuccessful. The pilot performed a forced landing in a field, resulting in substantial damage to both left and right wing struts.
A postaccident examination of the two-cylinder, two-stroke engine found that the airplane contained between 7 and 10 gallons of fuel with no contamination. There was evidence of spark from all of the ignition leads, and all four spark plugs were gapped within recommended specifications. The engine’s crankshaft rotated when force was applied to the propeller with no discrepancies noted. The engine contained adequate oil. The cylinders were checked for compression and the cylinder closest to the magneto had no compression. A fuel line leading to the cylinder was found with a zip-tie secured to it that reduced the interior circumference of the fuel line.
According to the airplane’s maintenance logbooks, the fuel lines were installed in March 2013 and inspected in June 2019. A condition inspection of the engine was completed in June 2023, with a total time of 564.7 hours. It is unknown when the zip-tie was placed around the fuel line.