Before revision: The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO).International Standards and Recommended Practices, Annex 5 to the Convention on International Civil Aviation, “ Units of measurement to be Used in Air and Ground Operations ” , ICAO, 4th Edition, July 1979.
After revision: The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO).International Standards and Recommended Practices, Annex 5 to the Convention on International Civil Aviation, " Units of measurement to be Used in Air and Ground Operations " , ICAO, 4th Edition, July 1979.