Rackliff and Kington's "Even the birds were walking" includes a statement that "St Eval was officially closed for flying when the cloud base was lower than 400 ft." That seems a remarkably high figure to me as 400 ft agl for St Eval is about 700 ft asl, and even with a cloud base of 200-300 ft agl visibility can be quite acceptable.

200 ft agl is about 500 ft asl, so an aircraft approached from the seaward side should have had no concerns about flying into cliffs since for the most part they are below 200 ft asl.

I'd appreciate any thoughts/comments about the statement from the forum's experts.

Brian

Edit PS. When did the RAF adopt colour codes?