CAPES MURPHY MOOSE — Marysville, WA

What happened

A witness at the pilot’s departure airport reported that the airplane’s take off appeared normal but that he saw black smoke emitting from the engine exhaust. Several witnesses in the vicinity of the accident site reported seeing the airplane flying at a low altitude and banking left before it descended nose down to the ground. One of these witnesses stated that the airplane appeared to be “out of control,” and another one of these witnesses reported that the airplane was descending “at a dangerous speed.” Other witnesses reported hearing the engine “pop,” “overrevving,” and “missing or puttering.” Two witnesses reported seeing another airplane near the accident airplane. One witness reported that the other airplane was slightly ahead of and above the accident airplane and that the airplanes were “unusually close.” The other witness reported that he saw the accident airplane banking left and it looked like it was going to cut off another airplane. The accident airplane then “plunged toward the ground.”

A review of radar data, GPS, and engine monitoring data revealed that the airplane departed the airport to the north at full engine power before it turned left near the destination airport. About 3 minutes into the flight, the engine rpm fluctuated between 2,260 and 2,900 rpm for 3 minutes before it returned to full power. Concurrently, another airplane, which could not be identified because both airplanes were being operated under visual flight rules and squawking “1200,” was approaching the airport from the south to what appeared to be a straight in approach to the same runway.

When the accident airplane was southwest of the destination airport, it started to turn north to final approach toward the destination runway while descending about 1,000 ft per minute (fpm) at full power. The unidentified airplane continued flying north directly toward the same runway. About 1.2 nautical miles south of the runway, the accident airplane was west and slightly north of the unidentified airplane. At their closest point, the two airplanes were within 0.22 mile of each other, and both were about 500 ft above ground level. The engine remained at full power and the airplane’s descent rate had increased to 4,000 fpm 7 seconds before the recorded data ended. The unidentified airplane continued north, flew over the runway, made a left teardrop turn over the airport, then departed the area toward the south. The destination airport does not have an air traffic control tower, and the common traffic advisory frequency is not recorded; therefore, the investigation could not determine if either pilot was communicating over the radio.

The accident pilot had recently built the airplane, and the accident flight was its second flight. The airplane’s first flight was about 1 month before the accident. After landing at the destination airport, the pilot refueled the airplane, and it experienced an unspecified electrical problem. The pilot then flew back to the departure airport. During landing, the airplane touched down hard and exited the runway. A witness reported that the engine did not sound like it was running “well” during high-speed taxi tests the day before the accident.

Examination of the airframe and engine revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation and the engine monitoring data indicated that the engine was at full power. It could not be determined if the pilot’s attention was distracted by an unknown issue encountered inflight. It is likely that the pilots in both airplanes were not communicating over the common airport traffic frequency or adequately monitoring traffic in the airport environment. The accident pilot likely descended the airplane during a left turn to avoid a collision with the other airplane and did not have sufficient altitude to clear terrain.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.