What happened
Following delays caused by intense weather at the departure airfield, a Beech 18 began its flight despite briefings that indicated severe thunderstorms, potential tornadoes, large hail, and significant wind gusts. The aircraft lacked onboard weather radar or a storm scope to navigate the incoming weather. After an initial period of uneventful cruising at 10,000 feet lasting approximately 1 hour and 50 minutes, air traffic control lost radar contact with the aircraft. Thirteen minutes after the loss of contact, the pilot transmitted a 'Mayday' distress signal, stating the plane was going down. Radar data from the final moments indicated the aircraft was descending at a rate of 6,000 feet per minute.
Findings
Investigations into the operator's documentation revealed that the aircraft was not officially approved for Part 135 operations. Instead, the company utilized a fraudulent approval document, which had been signed by an FAA Principal Operations Inspector, to seek authorization for flight within Canadian airspace. Furthermore, the pilot's experience in the Beech 18 was limited to 6.3 hours of solo flight time, which had been recorded as dual instruction. Despite this limited experience, the pilot had recently completed a brief 1.6-hour evaluation and received check airman authorization for all models of the aircraft type.