On July 14, 2019, about 0630 mountain daylight time, a Cessna P206, N131DV, sustained substantial damage when it was involved in an accident near Sulphur Creek Ranch Airport, Cascade, Idaho. The pilot and two passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The pilot’s family owned the remote ranch, which was only accessible by hike or flying to the private-use landing strip near the property. The purpose of the accident flight was for the pilot to transport two family members from the ranch back to their home in Wyoming. The pilot stated that he had intended to first land in Driggs to obtain more fuel before continuing to Gillette, Wyoming. The pilot stated that after a normal preflight and engine run-up, he taxied for a departure to the east (totaling a 7 to 8 minutes of engine operating time). After the airplane departed and reached about 75 feet above ground level (agl), the engine rpm smoothly deteriorated to a total loss of power. The pilot relieved the control column back pressure and configured the airplane in a nose-low pitch attitude in an attempt to avoid stalling and to make an off-airstrip landing. The pilot could not recall his next actions but thought he may have unintentionally turned the fuel selector to the OFF position after the loss of power thinking he was switching to the other (fuller) wing tank. The airplane collided with the thick brush off the end of the runway and nosed over, coming to rest inverted. The pilot estimated that there were about 30 gallons of fuel in each tank. He did not know the reason for the loss of engine power but opined that he possibly leaned the engine too aggressively for the density altitude. Investigators performed a postaccident examination on the engine and airframe. Control continuity was established from the cockpit's engine controls to the engine. The fuel selector was in the OFF position. The Continental Motors IO-550-F20BR engine, installed under a supplemental type certificate (STC) in July 2010, was intact and remained secure to the airframe. A test run of the engine was performed at the recovery facility. A fuel source was attached to the right inlet fuel line prior to entering the fuel selector. The engine was successfully started and run for over 5 minutes at various power settings from idle to about 1,500 to 1,600 rpm. A magneto check was conducted on the left and right magnetos with a minimal rpm drop on each magneto noted. The engine was shut down using the mixture control lever. During the engine run, when the auxiliary fuel pump was turned on HIGH, the engine ran rough and began to lose rpm until the mixture was leaned. The postaccident examination revealed no evidence of a malfunction or failure with the engine or airframe that would have precluded normal operation.