>AAR don't you think it would be much safer to say knots,
>flight level, ect. As if you pick the wrong one, you might
>find yourself in a lot of trouble!
Agreed, but the statement is clearly understandable by itself. "270" is speed. For turns ATC will specify a direction (left or right) to turn without which you'll be going 180 degrees from where the controller wanted you to go. Flight Levels are spoken "2-7-0" which is not easily confused with "270."
This is not normal or "approved" ATC communications technique, but still easily understandable just on the face of it. If receiver doesn't understand the instruction, the receiver can simply ask the controller's intent. Additionally, when taken in context of _all_ other radio traffic a pilot should be able to anticipate the need for ATC speed control in most instances (if he was paying attention).