Ryan International Airlines Flight 590 Crash (1991)

February 17, 1991

On the icy morning of February 17, 1991, Ryan International Airlines Flight 590, a McDonnell Douglas DC-9-15RC cargo jet carrying U.S. mail, crashed moments after departing Cleveland Hopkins International Airport. Both pilots aboard, the flight's only occupants, were killed instantly. The disaster exposed dangerous gaps in how the FAA, McDonnell Douglas, and the airline industry understood ice accumulation on aging DC-9 airframes.

A Routine Mail Run Turns Deadly

Flight 590 began as an unremarkable cargo run, hauling U.S. Postal Service mail from Greater Buffalo International Airport in Buffalo, New York, toward its final destination of Indianapolis International Airport in Indiana, with a scheduled stopover in Cleveland, Ohio. The aircraft, a McDonnell Douglas DC-9-15RC operated by Ryan International Airlines, touched down at Cleveland Hopkins International Airport in freezing, snowy conditions typical of a Midwestern February. After a brief ground stop, the two-person flight crew prepared for departure toward Indianapolis. Neither pilot survived to explain the decisions made during that stop, but investigators later pieced together that the aircraft sat on the ramp accumulating frost and ice while precipitation fell steadily around Cleveland. When the DC-9 lifted off from Runway 23L, it climbed only briefly before losing control and slamming into the ground near the airport, erupting in flames. Emergency crews arriving at the wreckage found no survivors. The crash occurred so quickly after liftoff that air traffic controllers had little warning something had gone wrong, and the loss of both pilots meant investigators would have to rely almost entirely on physical evidence, weather data, and cockpit recordings to reconstruct the flight's final seconds.

The NTSB Investigation Points to Ice

The National Transportation Safety Board launched a thorough investigation into the crash, examining the wreckage, weather conditions, maintenance records, and crew procedures. Investigators determined that the DC-9 had not been deiced before its doomed takeoff attempt, despite conditions at Cleveland Hopkins that were conducive to ice and frost forming on the wings and control surfaces. Even a thin layer of ice on a wing can disrupt airflow enough to cause a sudden, uncontrollable stall shortly after rotation, a phenomenon well documented in aviation but one that the flight crew apparently failed to recognize or address that morning. The NTSB's final report placed primary responsibility on the flight crew's failure to have the aircraft deiced prior to departure. However, investigators went further, identifying a broader systemic problem: the FAA, McDonnell Douglas, and Ryan International Airlines all lacked sufficient understanding of how icing specifically affected the DC-9-10 series aircraft, an older variant with wing and control characteristics that made it especially vulnerable to ice-related performance degradation. This finding suggested the crash was not merely a case of pilot error but also a failure of institutional knowledge and guidance that left flight crews without adequate training or clear procedures for handling icing risks unique to that aircraft type.

Lasting Impact on Aviation Safety

The crash of Flight 590 became part of a troubling pattern of icing-related accidents involving DC-9 and similar aircraft in the late 1980s and early 1990s, a period during which the aviation industry was still refining its understanding of cold-weather operations. In response to this and comparable accidents, regulators and manufacturers intensified efforts to improve deicing protocols, crew training, and aircraft-specific icing guidance. The FAA subsequently strengthened requirements around holdover times for deicing fluids and pushed for clearer, more standardized procedures to ensure crews understood exactly how long an aircraft could sit after deicing before ice or frost could reform. McDonnell Douglas also worked to provide more detailed guidance to operators of the DC-9-10 series regarding its specific icing vulnerabilities. Though Flight 590 claimed only two lives, its investigation contributed meaningful lessons to an evolving body of aviation safety knowledge, reinforcing that icing was not a generic hazard to be addressed with one-size-fits-all solutions, but a risk that varied significantly across different aircraft designs. The accident remains a case study in aviation safety courses, illustrating how a seemingly minor lapse, skipping deicing procedures, combined with insufficient institutional knowledge, can produce catastrophic consequences even on a routine cargo flight.