I wonder why most or all of that guidance on alt air operation comes from the PA46 corner though and whether is it PA46-specific? I guess one point is that few other piston aircraft are routinely flown is prolonged icing conditions. But sure P210s are as well. Plus there a a couple thousand FIKI SR22 out there by now..
You’re right to point out that what I say may well be PA46 specific, I have amended my post to avoid any ambiguity
denopa wrote:
the Jetprop where switching the ice door lowers performance significantly.
Do you have any numbers/percentage for “significantly”?
denopa wrote:
One of the only advantages of the piston PA46 vs the Jetprop where switching the ice door lowers performance significantly.
Yes, it lowers performance of the Jetprop to only be massively better performing than the piston. 
Emir: i don’t have time to look through the MMOPA posts but from memory, it was cutting about 25% off the climb rate. As Jason kindly notes, this reduces the Jetprop’s climb to only 3x that of the piston ;-)
I read that report in post 18.
I don’t think they make a rigorous case for their conclusion. They just present it as a done deal. They did not get the aircraft apart until days later and, wow, they found some water in the inlet duct…
