Anti-Ice vs. De-Ice
Gentlemen,
It's important to remember that the engine anti-ice system is just that...anti-ice. Allowing ice to build up could easily cause severe engine damage, flame out, etc. This is why it's important to have the engine anti-ice system ON prior to entering icing conditions.
It does not hurt anything to have the engine anti-ice system ON (if you're anticipating icing conditions), and then discover it really wasn't needed. Yes, you're burning a bit more fuel. But, the other side of the coin is: How much money do you save over the lifetime of your career by damaging an engine? You can buy a lot of fuel for the cost of such an occurrence.
We've beaten this topic to death many times, here, in PPrune. My advice is to follow your company's SOP. It protects you, and, in this regard, it will protect your engines.
I've flown with many guys over the years who have their own 'techniques'. Not a good idea. And, some guys will pretend that, with having their own 'techniques', they employ some degree of piloting proficiency that others lack. WRONG!!!!!
Follow the SOP.
My philosophy...when in doubt (about the possibility of icing) turn on the engine anti-ice. (This covers the 'anticipated' clause of the SOP.)
Another interesting note...some erroneously believe that, under certain atmospheric conditions, turning on engine anti-ice could actually increase the likelyhood of engine flameout and/or damage due to icing. WRONG!!!!!
If this were true, there would be SOPs/limitations regarding this.
When in doubt, use it. The worst-case down-side...you've wasted a bit of fuel.
Fly safe,
PantLoad