What happened
Operating under night instrument flight rules (IFR), the pilot was conducting a medical specimen transport mission when the aircraft began a series of unusual maneuvers. During the initial climb, air traffic control notified the pilot that the selected transponder code, 2501, was incorrect and provided instructions to switch to code 2531. Following this interaction, the aircraft reached a peak altitude of approximately 3,300 feet before entering a right-hand descending turn.
Data from the enhanced ground proximity warning system indicated a rapid descent rate of 11,245 feet per minute, which triggered two separate "sink rate, pull up" alerts. The aircraft briefly climbed from 1,400 feet to roughly 2,000 feet, but then entered a subsequent turning descent. The aircraft eventually struck the ground approximately 5 miles northeast of the departure airfield. The impact resulted in the aircraft being fragmented across a debris field measuring roughly 800 feet in length and 300 feet in width. There were 0 fatalities reported in the provided text.
Findings
Post-accident inspections of the aircraft revealed no mechanical failures that would have prevented the pilot from maintaining control, and the engine showed no signs of pre-impact issues. However, investigators discovered an open resistor within the flight computer responsible for autopilot control. It remained unclear whether this resistor failed during the flight or upon impact. If the resistor was open during flight, the autopilot might have displayed an active engagement mode while failing to actually move the pitch and roll servos.
While the pilot was experienced in night IFR operations, the accident circumstances are consistent with spatial disorientation. The investigation noted that the requirement to reset the transponder may have acted as an operational distraction, disrupting the pilot's instrument scan. Additionally, if the autopilot was engaged and malfunctioning due to the resistor, a failure to notice the lack of actual control could have contributed to the loss of attitude awareness and the subsequent crash.