What happened
On the scheduled flight from Marion-Williamson County Airport to St. Louis, an FH-227B operated by Ozark Air Lines was conducting an instrument flight rules (IFR) arrival. After departing Marion at 17:05, the aircraft proceeded toward its destination via the V-335 airway. During the descent, air traffic controllers directed the crew to perform a 360-degree turn to avoid weather cells.
As the aircraft approached St. Louis, the controller provided radar vectors through an area containing thunderstorm cells located south and southeast of the airport. The flight was cleared for an ILS approach to runway 30L. During the final stages of the approach, the local controller noted a heavy rain shower moving across the runway approach end, which the crew acknowledged.
After passing the Outer Marker, the aircraft descended below the established glide slope. The plane first impacted treetops approximately 55 feet above the terrain before crashing into a hillside in the Normandy district, less than two miles from the threshold of runway 30L. The accident resulted in 38 fatalities and 2 survivors.
Findings
The crash was caused by the aircraft encountering a downdraft after the captain chose to proceed with an instrument approach into a thunderstorm. This decision was likely compounded by a failure to receive timely severe weather alerts from the National Weather Service, as well as an inadequate evaluation of terminal area weather conditions by both the flight crew and the dispatcher.