WOK, most -- if not all -- those (non-Soviet) fuels were readily available worldwide and about the same cost in the late 1960's? The Concorde's fuel required no special filtering or additives which may have set it apart from the requirements of other jet a/c?
By comparison, what fuel was the 707 and 727 burning then?
When I read the passage in one book or another about the special fuel required, it took me aback. I presume now that source was mistaken.
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R. J. Emery