During the years 1982 through the present, there have been over 150 inflight icing related accidents within the United States involving aircraft that were equipped for flight in icing (not all of them were certificated for flight into known icing). Many of these accidents involve Part 23-certificated aircraft, where smaller scale may play a very powerful role. But the common perception of an icing accident as simply too much ice followed by a stall is based more on the old CAA cartoon depicting the effects of icing as “cumulative” than on what actually happens. These sixteen reports provide a cross-section of the types of events that have occurred. If United 21 and Northwest 5 represent the benchmark investigations of the 1940’s, then Simmons 4184 and Comair 3272 are the most comprehensive icing investigations of the 1990’s. Unfortunately, many of the lessons learned from all of these earlier accidents continue to be borne out by the investigations of the 21st century.
A number of these reports are not “blue-cover” NTSB reports, but simply the Factual and Probable Cause reports combined. There are many, many more of these within the NTSB data.
It is interesting to compare the the CVR transcript in the Circuit City accident (N500AT) and the interview with the captain of Northwest 5 (see Historical Reports). During the 65 years between these events, there have been hundreds of similar events, and this type of icing accident remains the dominant event type today in ice-protected airplanes. It would seem that, if we spent more time studying accident histories, we might prevent or at least mitigate any similar events in the future.