On October 22, 2023, at 0935 eastern daylight time, an experimental, amateur-built Avid Aircraft, N246ML, was substantially damaged when it was involved in an accident near Knoxville, Tennessee. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that after an uneventful preflight inspection and engine run-up, he departed runway 01 with the engine power set to 6,300 rpm. At 100 ft above the runway, he adjusted the engine rpm to 6,000. After about 1 minute of flying at an altitude of 400 ft agl, the engine decreased from 6,000 rpm to totally stopped within seconds. The pilot elected to land on a riverbank; however, the airplane contacted trees and a metal fence before coming to rest in the river. The pilot conducted a postaccident examination of the airplane’s two-stroke engine and found that the piston in the power take-off cylinder had seized during the accident flight. The pilot subsequently started the engine and it engine operated without any anomalies. The airplane’s most recent maintenance records were not located. The pilot reported the engine had accumulated about 177 hours of operation before the accident. He also stated the airplane had not been flown for about 10 years and was in poor condition when he purchased it. He reported that he did not perform any internal maintenance on the engine but did extensive work on the external components.