WPR19FA178

The pilot and passenger departed on a local flight in the amphibious airplane from a paved runway. The passenger described the airplane's rate of climb after takeoff as "slow" and stated that it was apparent that the airplane would not clear the 50-ft-tall trees ahead. A witness described the airplane as "struggling to gain altitude" and noticed a "definite power loss." The pilot performed a forced landing to a river, where the airplane immediately nosed over and began filling with water. The landing gear was found in the extended position and the water rudders were retracted. The landing gear position indicators were operational and also indicated that the landing gear was extended. The position of the landing gear likely resulted in the airplane nosing over upon impact with the water. Examination of the engine revealed that the muffler baffles had broken at the weld point. The left muffler baffling moved freely inside of the muffler. The right muffler baffling was turned 180° and was obstructing the exhaust outlet. A test run of the engine with the mufflers installed was unsuccessful; however, upon removal of the mufflers, the engine performed with no anomalies. There is no requirement to check the inside of a muffler during annual or 100-hour inspections to ensure that the baffling is intact. It could not be determined as to how long these mufflers had been in this condition. It is likely that the airflow restriction of the separated baffling resulted in a partial loss of engine power and the airplane's subsequent inability to climb after takeoff.

The last maintenance performed was dated June 4, 2019, at a tachometer time of 967.7 hours. The exhaust system was sent for repairs during an annual inspection on June 22, 2011, at an airframe total time of 794.7 hours. On June 22, 2019, about 1040 Pacific daylight time, an amphibious Maule M-7-235B airplane, N118G, was substantially damaged when it was involved in an accident near Sunriver, Oregon. The pilot was fatally injured, and the pilot-rated passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the passenger, the purpose of the flight was to see how the airplane performed with two people onboard. The pilot taxied the airplane to the runway, performed an engine run-up with no anomalies noted, and began the takeoff roll. The passenger stated that the throttle was full forward and the engine did not sound abnormal. He stated that the pilot rotated the airplane about 65 knots with about 1,000 ft of the 5,461-ft-long runway remaining, and the airplane lifted off the runway into ground effect. He recalled that once the airplane climbed out of ground effect, the rate of climb was slow, and it was apparent that they would not clear the 50-ft-tall trees across the river. The pilot maneuvered the airplane to the left, and the airplane touched down on the Deschutes River, nosed over, and began to fill with water. The passenger said that he was unaware that the river was the intended forced landing site until seconds before touchdown. Two witnesses who saw the takeoff described the airplane as low and struggling to gain altitude. One witness stated that the engine "sounded like the pilot had not throttled up enough or the engine was bogging for some reason." He stated that there was a "definite power loss" but no "engine sputter or misfire." The airplane turned slowly to the left, continued losing altitude, and cleared large trees lining the Deschutes River. The witness then heard a loud pop, saw the splash, and the tail "flip over." Another witness said that the airplane impacted the tops of the trees. An autopsy was performed by the Deschutes County Medical Examiner's Office. According to its report, the cause of death was drowning. A toxicology screen performed by FAA's Forensic Sciences laboratory detected no carboxyhemoglobin or ethanol in blood. Rosuvastatin was detected in blood and liver tissue; rosuvastatin is not impairing. The landing gear was found in the extended position. The water rudders were found in the retracted position. The pontoons (floats) were equipped with four visual landing gear position indicators. Each indicator was operational and indicated that the wheels were extended. Supplement 2 of the Maule Airplane Flight Manual stated, "Do not land on water unless the landing gear is fully retracted." The engine was examined following recovery from the river. During the first attempt to run the engine, the engine started but would notmaintain power. Examination of the mufflers revealed that the baffles had broken off at the weld point. The left muffler baffling moved freely inside of the muffler. The right muffler baffling was turned 180° and obstructed the outlet port. Both mufflers were removed, and the engine was restarted; the throttle was advanced to about 1,500 rpm. A magneto drop was conducted. A loss of about 100 rpm was noted when the magnetos were isolated. Power was then advanced to 2,400 rpm with no anomalies noted. Per the maintenance manual TLC-M-7-235A/B, rev. C, dated April 13, 2016, and Part 43, Appendix D, there is no requirement to check the inside of a muffler during annual or 100-hour inspections to ensure that the baffling is intact. How long the mufflers had been in this condition on the accident engine could not be determined.