History of Flight
On August 14, 2019, about 1853 Pacific daylight time, an experimental, amateur-built Murphy Moose, registration N525SG, was destroyed when it collided with terrain near Marysville, Washington, south of Arlington Municipal Airport (AWO), Arlington, Washington. The pilot was fatally injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
A witness at the departure airport reported that the day before the accident, he observed the pilot conducting high-speed taxi tests on the runway and noted that the engine did not sound like it was running well. On the day of the accident, the witness saw the airplane take off; the takeoff appeared normal, but black smoke was visible from the engine exhaust.
Several witnesses near the accident site reported seeing the airplane flying at low altitude and banking left before it descended nose-down to the ground. One witness stated the airplane appeared to be out of control; another reported it was descending at a dangerous speed. Three witnesses reported hearing the engine pop loudly then rev high, sound like it was possibly overrevving, or missing or puttering.
Two witnesses reported seeing another airplane near the accident airplane. One witness said the other airplane was slightly ahead and above, and the airplanes were unusually close. The other witness saw the accident airplane banking left and appearing to cut off the other airplane, then plunging toward the ground.
A review of radar, GPS, and engine monitoring data revealed the accident airplane departed Frontier Airpark (WN53), Lake Stevens, Washington, to the north at full power, then turned left while north of AWO and continued south. About three minutes into the flight, engine rpm fluctuated between 2,260 and 2,900 rpm for three minutes before returning to full power. Concurrently, another airplane, squawking 1200 and on visual flight rules, approached AWO from the south. When the accident airplane was southwest of AWO, it turned north to final approach toward runway 34, descending at about 1,000 ft per minute at full power. The unidentified airplane continued north toward runway 34. At their closest point, about 1.2 nautical miles south of the runway, the two airplanes were within 0.22 nautical mile of each other, both at about 500 ft above ground level. The accident airplane's engine remained at full power, and its descent rate increased to 4,000 ft per minute seven seconds before the recorded data ended. The unidentified airplane continued north, flew over runway 34, made a left teardrop turn over AWO, and departed south. AWO has no air traffic control tower, and the common traffic advisory frequency is not recorded.
Personnel Information
According to the Federal Aviation Administration, the pilot's medical certificate expired on December 31, 2015. No record was found indicating the pilot had applied for BasicMed. The pilot's logbook indicated that as of the last entry dated December 29, 2014, he had a total of 375 hours of flight experience. Throughout the logbook, there were no entries related to flying a Murphy Moose. The last recorded biannual flight review was dated July 9, 2014, conducted in a Beech 19 airplane.
Aircraft Information
The pilot had recently built the airplane, and it was issued a special airworthiness certificate on June 6, 2019. The pilot's first flight was on July 20, 2019, from WN53 to AWO, where the airplane refueled and then experienced an unspecified electrical problem. During the return landing at WN53, the airplane touched down hard and exited the runway.
Wreckage and Impact Information
The airplane impacted a field about 1 mile south of runway 34 at AWO. The debris path was about 334 ft long, oriented on a magnetic heading of about 348°. The first identified point of contact (FIPC) was an area of displaced dirt consistent with impact of the left float, followed by an area of disturbed dirt consistent with impact of the right float. A large crater containing wooden propeller blade fragments was located about 61 ft from the FIPC. Portions of the propeller, front float wheel assembly, left and right wingtips, engine airbox assembly, and portions of the engine cowling were found at different points farther along the debris path. The main wreckage came to rest inverted about 289 ft from the FIPC, with left and right floats at 309 ft and 334 ft, respectively.
Both wings remained partially attached to the fuselage and exhibited extensive damage. The cabin area was fragmented and torn open. The empennage exhibited impact-related damage but remained attached. Flight control continuity was established throughout the airframe. The fuel system was breached. A blue liquid consistent with 100LL fuel was observed in the fuel strainer bowl, and the screen was clear of debris. The engine remained attached to its mounts and firewall. All accessories except the carburetor remained attached. The throttle cable was separated from the carburetor, consistent with impact damage. Engine control continuity was established. The propeller hub remained intact; the three blades were separated or splintered near the blade root. Oil lines to the oil cooler exhibited impact damage, and oil was observed throughout the accident site and wreckage. Examination of the airframe and engine revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation.