I've recently changed some of the settings I use in Active Sky Evolution and FSUIPC (now using DWC).  Things have been working out fine for months, until recently, when I started flying the PMDG J41 again after not touching it for a couple of months.  It seems that every time I take it up, I'm getting Ice (the J41 displays it graphically too).  Last time I flew this aircraft was last winter when I was flying in very cold, but very clear conditions...I don't recall ever seeing ice on this plane ever before, as long as I've owned it, even when flying through rain squalls at temps below 0 C.

I even had some problems just using the default "Fair Weather theme", without Active sky even running.  Thus, I sense there is something screwy going on.  (Just confirmed that this is happening out of KSEA, Fair Weather, TAT of 8c, alt 6000 feet)

In the following screeny, the TAT is 1C, alt is about 8000 feet, and even though there are a few clouds, I haven't been flying through any of them, or any visible moisture, yet I'm icing up like a popsicle.  Is something screwed up here?  Before concluding that there is indeed something wrong with weather program/airplane/my setup, etc, I wanted to learn a little more from real pilots about icing conditions.

What are the criteria for icing conditions?

aeroart wrote on Mar 28^th, 2011 at 8:34pm:


Yes, that is what I thought...since posting my original, I conducted some test flights in Fair/Good conditions (without the 3rd party weather), and determined that there is most definitely something going wrong with my setup.  I can confirm that I'm Icing up consistently at 6000 feet, 6-8C TAT (don't know what the OAT is), in fair weather conditions.

My next step is to uninstall/reinstall J41, because I suspect that somewhere along the way, one of the many .ini or configuration files for it must have gotten hosed up (a shot in the dark, but what else to do, I don't know).  After that, who knows...

Did the reinstall.  Same thing.  Haven't the foggiest clue.    I've spent so much time flying approach practice in this plane, and so little time flying actual "commuter flights" at altitude, that it is difficult to determine whether I'm encountering an anomaly, or whether what I'm seeing is actually realistic.  What It looks like so far, this particular aircraft modeling sees every cloud "layer" in the sim as an icing hazard, whether or not you are actually in a cloud or not, and from there, the only criteria is whether or not the SAT is at or near 0...then it starts adding gobs of ice to the airframe.  Anybody else fly this plane, and seen anything similar, and if so was the ice formation reasonable (realistic)?

Brett_Henderson wrote on Mar 29^th, 2011 at 7:36am:


A career flight simmer like yourself doesn't have the J41?    To answer your question, I'm not sure if it is by guage or .mdl.  Maybe both? 

Even though I've been flight simming for years, I've never signed up to be a member of avsim/pmdg forums (I don't like the attitudes I see over there, to put it in a nutshell), otherwise I would ask PMDG directly in their J41 section.  Even so, I read Avsim religiously, and  I see no posts there complaining about the icing behavior of this particular plane.

Most of my previous time in this airplane was spent doing approach practice and flights in the Gulf of Mexico/Caribbean region so I probably just never noticed any of this before.

Like you said, Brett, it is probably just modelled a bit overzealously.   I can believe Icing in the conditions depicted in the screenshot, but this is the only plane that gives me an ice warning during the "Fair Weather" FSX theme.

[quote author=Brett_Henderson link=1301357499/5#5 date=1301419676]I never got the J41.. I'm not comfy with MSFS turbine modeling..  [quote]

For what its worth, I'm not either.  The J41 and the new Royal Turbine Duke are "special" though, in the sense that the developers have taken massive steps to "work around" the limitations of the default FSX turbine modelling.  Those 2 are the only Turboprops in my Hangar at this time.  I stopped flying the otherwise excellent Piper Cheyenne payware for the very reason that it didn't seem to model the relationship between torque and RPM the way it should, and didn't pay any attention to over temps, at least so far as a non-real-pilot like myself can understand it.

If I continue to see unrealistic, problematic icing on the J41, the good news is that the Config utility allows you to simply turn it off, which is something I might do, although that may only turn off the graphical component, and not the icing itself.  I haven't noticed any actual loss of lift type problems from the ice buildup, but I'm not saying it isn't there....

Turning on the Anti Ice systems for the Turbine Inlet uses bleed air, so you do take a hit to your thrust.   I guess cycling the boots, however, shouldn't be a problem.

Surprised there aren't more people on SimV who have this plane

Quote:

In real-world ops, anti-ice is required at +6 C or below and visible moisture. Visible moisture means you can see clouds. You don't have to actually be in them. If the clouds are in your neighborhood and you can see them, that's visible moisture. The reason for the +6 is because local airflow around the airframe can cause adiabatic cooling well below what the free-air temp is.

From your screen shot and stated conditions, icing would be a possibility. I've had ice accumulation on the 737 (real-world) under the windshield wipers flying through nearly cloudless skies in the Pacific Northwest and Northern Europe. I'm not familiar with Active Sky Evolution or DWC, but it looks like they're doing a good job of replicating some realistic conditions.