What happened
The flight was cleared by approach control to descend and maintain an altitude of 7,500 feet. The pilot was instructed to turn right to a heading of 040 degrees for an ASR (Airport Surveillance Radar) approach to Pueblo Memorial Airport. The minimum descent altitude (MDA) for this procedure was established at 5,200 feet.
The crew read back the clearance as "Left to one forty five two zero zero." Approach control corrected the heading instruction to 040 degrees, which the flight acknowledged. There were no further communications recorded with the aircraft after this exchange.
The aircraft was traveling at an estimated speed in excess of 200 mph when it struck tundra terrain while in level flight on a heading of approximately 040 degrees.
The investigation
A post-accident autopsy of the copilot revealed significant medical findings. The trachea, bronchi, and lungs contained aspirated gastric contents, which included skeletal muscle fibers. This indicated that the copilot had vomited prior to impact.
Additional evidence from another company pilot reported that the copilot had vomited during a flight on November 14, 1982, suggesting a potential recurring medical issue.
Findings
The aircraft was in level flight when it impacted terrain. The lack of further communication and the medical findings suggest sudden incapacitation of the crew, likely due to the copilot's condition.