On August 24, 2020, about 0935 central daylight time, a Cessna R182 airplane, N639RR, was substantially damaged when it was involved in an accident near Crowley, Louisiana. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight. According to the pilot, the preflight engine run-up and takeoff were normal. About 30 minutes into the aerial observation flight, the engine began "popping" and running rough. The pilot was unable to maintain sufficient engine RPMs and elected to return to the departure airport for a precautionary landing. Based on the airplane's location relative to the runway orientation, the pilot performed a downwind landing. During the approach, the airplane was "a little high and fast;" however, the pilot was committed to the landing due to the reduced engine performance. The airplane touched down, overran the end of the turf runway, impacted a ditch and came to rest upright. The pilot reported the airplane sustained substantial damage to both wings and the fuselage. Postaccident examination of the engine by the operator revealed the No. 4 engine cylinder exhaust valve was stuck which resulted in a bent push rod and partial loss of engine power. Following the accident, hurricane activity damaged the operator's facility and the accident airplane, and further examination of the engine was unable to be conducted.