Ian W: No JP 4 I ever flew could get anywhere near that. KP,s estimate sounds about right!
Lemain, Perhaps I came over a little strong.
However, many years ago I was a CAA IMC examiner (and an RAF IRE) and was frequently disappointed at the poor understanding by ppl holders of altimetery, something I tried to correct. I still hear of height and altitude being confused and their exact meaning being misunderstood.