WPR11LA311

The airplane's engine stopped making sufficient power to maintain a climb, so the pilot decided to turn back toward the airport. However, after he flew into a valley, he realized that the airplane would not make it back to the airport. After seeing power lines along the airplane's flightpath, he turned the airplane toward an open field. The airplane subsequently hit the ground hard and then hit a tree, which separated the right wing from the airframe. During the postaccident engine examination, the muffler was disassembled. One internal baffle cone was found separated from the end plate and was blocking the opening of the muffler. Upon shaking the muffler, the baffle cone was free to move around within the muffler assembly. The other baffle cone had a hole eroded in its center. Internal engine failures can cause partial or complete engine power loss by restricting the flow of the exhaust gases. If pieces of the internal baffling break loose and partially or totally block the flow of exhaust gases, an engine failure can occur. It is likely the exhaust gas was partially or totally blocked by the separated baffle cone during the flight, which resulted in a loss of engine power.

The FAA Publication Aviation Maintenance Technician Handbook – Powerplant, Volume 1, Chapter 3, describes induction and exhaust systems. One section of that chapter discusses internal muffler failures. It states that internal failures (baffles, diffusers, etc.) can cause partial or complete engine power loss by restricting the flow of the exhaust gases. If pieces of the internal baffling break loose and partially or totally block the flow of exhaust gases, engine failure can occur. On July 5, 2011, about 1900 Pacific daylight time, a Cessna R182, N7392X, collided with a tree during an off airport forced landing following a loss of engine power during climb to cruise altitude after takeoff from Hesperia, California. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot and one passenger sustained minor injuries; the airplane sustained substantial damage from impact forces. The personal cross-country flight departed Hesperia about 1855 with a planned destination of Adelanto, California. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated that he had flown to Hesperia from Adelanto earlier that evening, and purchased about 29 gallons of fuel. During the climb to cruise, the airplane was unable to climb, and the pilot turned back toward the airport. He flew into a valley, and realized that the airplane would not make it back to the airport. He saw power lines in his flight path, and turned toward an open field. The airplane hit the ground hard, and then a tree, which separated the right wing from the airframe. Fuel spray from the wing set a car on fire. The airplane spun around, and came to rest with the nose on the ground, and the left wing and tail resting against a house. Investigators examined the wreckage at Aircraft Recovery Service, Littlerock, California, on July 14, 2011. A detailed report is part of the public docket for this accident. Examination of the airframe and engine revealed no anomalies that would have precluded normal operation. Investigators disassembled the muffler, and noted that one cone-shaped baffle had separated from the end plate, and was blocking the end opening of the muffler. Upon shaking the muffler, the cone was free to move around within the muffler assembly. The other cone had a hole eroded in its center.