On December 25, 2018, about 0948 mountain standard time, an experimental amateur-built RV-6 airplane, N711JK, was destroyed when it was involved in an accident near Watkins, Colorado. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he purchased the airplane about 2 months before the accident. He had an airframe and powerplant mechanic conduct a prepurchase inspection who advised the pilot that the fuel and oil lines needed to be replaced. The pilot, who also held an airframe and powerplant license, replaced all the fuel lines about 1 month before the accident. Subsequently, he flew the airplane about 1.5 hours before the accident flight. The pilot reported that he departed from Front Range Airport (FTG) Watkins, Colorado (the airport has since been renamed to Colorado Air and Space Port Airport [CFO]), about 0920 heading east. He was planning to fly approximately 8 to 10 miles east to check the navigation system indications on the runway 26 instrument landing system approach and to conduct touch-and-go landings in the traffic pattern. During initial climb for the second touch-and-go landing and once the airplane reached between about 200 and 300 ft above ground level near mid-field, the pilot smelled an unusual odor. He looked inside the cockpit and saw flames coming from the floor forward of his rudder pedals. He added that he “immediately rejected the takeoff” and transmitted a “Mayday message stating the airplane was on fire.” He conducted a normal three-point landing on the departure runway, exited the runway onto an adjoining taxiway, and then stopped the airplane. The pilot turned off the fuel valve, shut down the engine with the mixture control, turned off all the electrical switches, and then exited the airplane. A postcrash fire ensued, which consumed the airplane. Postaccident engine examination revealed that all four fuel lines exhibited thermal damage and soot on their exteriors, consistent with exposure to fire. An end of one of the fuel lines contained soot deposits in the first three threads of the line’s attachment fitting.