CEN22LA012

The pilot reported that after leveling off from a descent and applying power, the engine began to lose power intermittently. Shortly thereafter, the engine lost all power and could not be restored. During a forced landing, the airplane impacted a tree, resulting in substantial damage to the fuselage and left wing. About 10 minutes before the descent, the pilot switched from the right fuel tank to the left fuel tank, which contained about 13 gallons of fuel. Although a postaccident examination revealed a worn piston and cylinder, no mechanical malfunctions or anomalies were discovered that would have precluded normal operation. Fuel was available to the engine as evidenced by the injector pump function, no air obstructions were noted, and both magnetos produced bright blue spark when tested.

On October 8, 2021, about 1325 central daylight time, a Stinson 108 airplane, N677JD, sustained substantial damage when it was involved in an accident near Wildwood, Arkansas. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal cross-country flight. The pilot reported that after he leveled from a descent and increased throttle, the engine “began to cough and cut out intermittently.” Shortly thereafter, the engine lost all power, and the propeller began to windmill. He immediately verified the mixture was full rich, applied the carburetor heat, and checked the magnetos, but could not restore engine power. He stated that about 10 minutes before the loss of engine power, he had switched from the right fuel tank to the left fuel tank, which had about 13 gallons of fuel remaining. The pilot executed a forced, power-off landing to a golf course, and the airplane impacted a tree, which resulted in substantial damage to the fuselage and left wing. During a postaccident examination of the Franklin 6A4-150-B3 engine, fuel was ejected from the carburetor when the butterfly valve was manipulated. The top spark plug from the No. 2 cylinder was bright white, consistent with exposure to high heat, and the No. 5 cylinder and piston contained evidence of oil present past the cylinder rings. Both magnetos were removed and tested using a hand drill with all terminals producing bright blue spark. No obstructions were noted within the air induction system and the examination revealed no pre-impact mechanical malfunctions or anomalies that would have precluded normal operation.