On October 3, 2025, about 1720 central daylight time, a Cessna 182RG airplane, N4609S, was substantially damaged when it was involved in an accident near Cottonville, Iowa. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that during cruise flight he noticed an increase in engine rpm. He attempted to increase the pitch of the propeller to decrease engine rpm, but there was no response from the engine. The pilot declared an emergency with air traffic control and was cleared to descend to 4, 000 ft mean sea level (msl) and to proceed to Dubuque Regional Airport, Dubuque, Iowa. The pilot stated that as he leveled at 4,000 ft msl, he heard a sound similar to an engine misfire, and the engine immediately shook “violently” and ran rough as the airplane started descending rapidly. The pilot noticed the engine oil pressure gauge had dropped to zero. The pilot executed a forced landing to a road. During the rollout, the left wing struck the shoulder of the road, the airplane departed the roadway and impacted a barbed wire fence. The airplane sustained substantial damage to the right-wing strut, right horizontal stabilizer, and the fuselage. The airplane was retained for further examination.