Accident Overview
On August 21, 2019, at approximately 1338 central daylight time, a float-equipped Stinson 108-3 airplane, registration N647C, was substantially damaged during a forced landing near Grand Rapids, Minnesota. The pilot sustained minor injuries. The aircraft was registered to a private individual and operated by the pilot as a personal flight under Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight was originating at the time of the accident.
Accident Sequence
The pilot reported that he allowed the engine to warm up for about 15 minutes before takeoff from Lily Lake, located immediately north of the Grand Rapids/Itasca County Airport (GPZ). He used carburetor heat during the run-up and before takeoff. The takeoff was normal. Shortly after establishing climb power, the pilot noticed a reduction in power, although the engine continued to run smoothly. He turned the airplane for a left downwind landing on Lily Lake. Several seconds later, the engine popped twice and quit completely; the propeller continued to windmill. Determining that the airplane lacked sufficient altitude to reach the lake, the pilot executed a forced landing to a grass area near the water treatment plant northeast of the airport.
Postaccident Examination
A postaccident examination revealed damage to the aft fuselage, left wing, left horizontal stabilizer, and right float. The right wing appeared intact except for minor deformation at the wing tip. The left-wing fuel tank was dislocated from the wing, and grass at the location where the tank came to rest was blighted, consistent with fuel exposure. Approximately 20 gallons of fuel was recovered from the intact right-wing fuel tank.
The engine remained securely attached to the engine mount. The examination found no anomalies with the engine, its accessories, or related airframe components. An engine test run was conducted; the engine started without difficulty on the first attempt and ran smoothly. Magneto and carburetor heat checks were normal, and engine oil pressure remained within normal operating limits. No anomalies consistent with an inability to produce rated power were observed.
FAA Documentation
According to documentation issued by the Federal Aviation Administration, the possibility of carburetor icing at glide power existed at the time of the accident.