What happened
Following takeoff, the pilot encountered difficulties transitioning from the airport tower frequency to the departure control frequency. While communications with the tower indicated the aircraft's radio was functioning correctly on that specific channel, the pilot was unable to switch to the instructed departure frequency. Consequently, the pilot received authorization to return to the departure airfield.
During the return flight, the pilot continued to attempt to resolve the radio issues via radio transmissions. Flight tracking data indicated that while performing a left base turn toward the final approach, the aircraft flew perpendicular to the runway approximately 1,000 feet from the aimpoint, descending to a pressure altitude of 200 feet. The aircraft then performed a right turn roughly 0.5 miles from the runway before turning left toward the runway again. During this maneuvering, the airspeed dropped to approximately 53 knots, and the bank angle increased until the aircraft experienced an aerodynamic stall and struck the terrain.
Findings
An investigation of the engines, airframe, and engine monitoring data found no evidence of mechanical failures or malfunctions that would have prevented normal operation. While toxicology reports identified the presence of diphenhydramine in the pilot's system, there was no evidence that the medication caused diminished psychomotor performance. The accident was attributed to the pilot becoming distracted by the non-critical radio malfunction, which led to an improper turn during the traffic pattern and a subsequent failure to maintain sufficient airspeed and bank angle.