On March 28, 2018, about 0830 eastern daylight time, an experimental Lancair IV-P, Canadian registration C-GSQQ, was substantially damaged when it was involved in an accident near Sebring, Florida. The private pilot and two passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. While inbound for landing, the pilot made multiple position reports on the airport's published common traffic advisory frequency (CTAF). He landed uneventfully on runway 01 after completing a GPS approach, exited the runway onto taxiway A4, and stopped. He reconfigured the airplane, performed the taxi checks, and noticed a Boeing 737 (B737) south of his position, facing south on a taxiway that paralleled the runway. He thought that the airplane was parked, and neither he nor the right front seat passenger recalled seeing any people on the ground around the B737. He noticed that the left engine cowling was missing, but he could not perceive whether either engine was running, adding that there were no barricades to block the taxiway. The pilot began taxiing westbound about 200 to 300 ft behind the B737 with no aileron control input applied, when the left wing suddenly rose, and the right wing contacted the taxiway. The airplane cartwheeled and came to rest upright on grass at the north edge of the taxiway with the nose landing gear fork and wheel assembly separated. He reported that the empennage was cracked and that there was damage to both wings at their roots, consistent with up-and-down flexing. Maintenance personnel onboard the B737 reported that they were in contact with personnel in two vehicles on the ground near the nose landing gear, but that they were not monitoring the CTAF. Both engines of the B737 were stabilized at 85% power while the individual in one vehicle had a portable radio transceiver and was monitoring the CTAF. That individual reported seeing the accident airplane when it first turned off the runway and crossed the hold short line. He attempted to communicate with the accident pilot on the CTAF, but his transmission was stepped on by another pilot, who was airborne and also attempting to warn the pilot that the B737's engines were running. He then began driving toward the accident airplane, but when it had encountered the jet blast, he broadcast to the B737 cockpit to secure the engines, then went to the accident airplane to render assistance. At the time of the accident, the B737 was positioned at the "north spot," one of its two pre-approved engine run locations on the airport. The executive director of the airport reported that there was an unwritten policy requiring his direct approval for maintenance engine runs for the B737. Personnel involved in the engine runs reported that airport personnel gave such approval; however, the director reported that neither he nor any airport staff gave approval for engine runs that day.