Investigation Summary
Flight 809 was a multi-stop regional service originating in Nashville with scheduled stops in Clarksville, Tennessee; Paducah, Kentucky; Cape Girardeau, Missouri; and Marion, Illinois. As the aircraft approached St. Louis after departing Marion, it entered a region of intense thunderstorm activity. Despite reports of hazardous weather from witnesses on the ground and a preceding TWA flight that had been forced to execute a missed approach due to severe updrafts, Flight 809 was vectored for an ILS approach to Runway 30L. During the final stages of the approach, the aircraft was observed by witnesses to suddenly ascend and then rapidly descend, a characteristic sign of encountering a microburst or severe vertical windshear. The aircraft was also reportedly struck by lightning shortly before impact. The FH-227B struck trees in a high nose-up attitude, indicating the crew was attempting to arrest the descent, but the downdraft exceeded the aircraft's performance capabilities. The fuselage broke into several sections upon impact in a residential ravine near the University of Missouri-St. Louis.
Final Conclusions
The NTSB determined the probable cause was the encounter with a severe downdraft during a critical phase of flight. Contributing factors included the captain's decision to penetrate a known area of severe thunderstorms rather than diverting or holding. This decision was found to be influenced by the air traffic controller's failure to convey the intensity of the storm cells and the dispatcher's improper assessment of the weather conditions, which led the crew to believe a safe landing was possible ahead of the weather front.
Photographic Evidence (1)
Video Analysis
Dark Skies: The Deadly Path of Ozark Flight 809 — A detailed look at the events of July 23, 1973, when Ozark Airlines Flight 809 crashed near St. Louis, exploring the weather conditions and the investigation into the disaster.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Systems & Failure Modes
Fuel Pump
The crew reported an inoperative fuel pump to maintenance shortly before the crash, though it was determined not to be a factor in the accident.
ILS Glide Slope
The aircraft descended significantly below the electronic glide path due to meteorological forces.
Interesting Facts
- 01The crash remains the deadliest aviation accident in the history of St. Louis.
- 02A TWA flight landing immediately before Flight 809 reported a strong updraft and performed a missed approach.
- 03Both the Captain and First Officer survived the crash, though the First Officer suffered from amnesia regarding the event.
- 04Four passengers were thrown clear of the wreckage upon impact and survived.
- 05The aircraft was found in a high nose-up attitude, suggesting a last-moment attempt to climb out of the downdraft.
Safety Actions & Advisories
Weather Reporting Improvements
The accident highlighted the need for more timely and accurate transmission of severe weather data from the National Weather Service to Air Traffic Control and subsequently to flight crews.
Windshear Awareness
The crash contributed to the early understanding of microbursts and downdrafts, eventually leading to better pilot training for windshear recovery.