In our mob it's on if in visible moisture below 10C. There is no bottom limit, well if there is I have comprehensively missed it!
Not sure what Hogg is on about, we cruise it at M0.70 or thereabouts, not much different to the fuel economy cruise of certain Boeings, and of course the Jungle Jet.
We usually cruise it at FL270-FL290. I guess Hogg must have been a "low and slow" specialist!
Also, Hogg is factually incorrect in what he says... selecting of anti-ice on does not require a thrust lever adjustment (certainly not a forward one), and the extra fuel burn is negligible.
Sure you ever flew the 146, Hogg?
[This message has been edited by Raw Data (edited 17 April 2001).]