On March 29, 2020, at 1518 central daylight time, a Muse P51D airplane, N151JD, was destroyed when it was involved in an accident near Mesquite, Texas. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Witnesses reported that the pilot took off and turned to a right crosswind in the traffic pattern, followed shortly thereafter by a turn to downwind. The airplane then entered a gradually steepening right turn before transitioning to a steep nose down attitude which continued until impact with terrain. A review of Automated Dependent Surveillance – Broadcast (ADS-B) data revealed that the airplane entered a right traffic pattern after takeoff and leveled off about 1,800 ft mean sea level (msl) on crosswind before beginning a turn to downwind. About 1518:47, the airplane entered a descending right turn from about 1,700 ft msl. The final data point was recorded at 1518:53; the altitude was about 900 ft msl. The average descent rate over the last 6 seconds of data was approximately 8,000 ft per minute. A postaccident examination of the airframe and engine did not reveal any anomalies consistent with a preimpact failure or malfunction. However, the examination was limited by the extent of the impact and postimpact fire damage. Toxicology testing performed at the Federal Aviation Administration Forensic Sciences Laboratory found no drugs of abuse. The owner/builder reported the accident occurred during the third flight of the airplane. The plan was for the pilot to conduct airwork in the local area and to gather data to assist in determining airplane fuel consumption. After the second flight, the pilot informed the builder that he had inadvertently moved the fuel selector to the OFF position while attempting to change tanks. He was able to correct the situation and had no further difficulties. A friend of the pilot reported that the pilot had cut the second flight short because continuous right rudder input was required. For the accident flight, the pilot took off with full right rudder trim to counter act the right turning tendency.