[SOLVED 2658] Airframe Icing problem.

[flyingfudge]

Hi.     Flight out of Dublin yesterday at appx. 15.00 local time.      Outside air temp +10C & dew point +7C

There was no visible ice on the top or underside of the wing and the CAS was clear but on take-off the aircraft fell out of the sky. I re-ran the saved situation a couple of times with the same result but then de-iced and it flew normally.

A couple of questions. In that temperature scenario the likelihood of icing, especially of an accumulation that would prevent the aircraft from climbing is not realistic. Whether this is a shortfall of X-Plane's weather depiction or not, surely the presence of wing ice should be visually obvious on the aircraft regardless. I brought this up on Discord and someone kindly pointed me in the direction of a Lua script that interrogates X-Plane's icing datarefs and indeed it did show wing icing.

This is not a criticism of this excellent aircraft addon but merely an observation. If the aircraft is detecting ice on the wing regardless of whether X-Plane is correct in it's assumption then surely the only way that can be reported to the sim pilot is in a visual representation which in this case it didn't.

I understand that Toto has introduced many variables into icing such as overnight temperature, humidity and dew point etc. but in reality a 10C temperature in the middle of the afternoon on an aircraft that hasn't flown on that day would not have any significant ice and certainly not an accumulation of ice that would bring down an aircraft on take-off.

I'm enjoying every minute of this remarkable aircraft creation by Toto, Goran and the team but would appreciate your thoughts on my comments.

[leha74ru]

2 hours ago, flyingfudge said:

Lua script that interrogates X-Plane's icing datarefs and indeed it did show wing icing.

Can you share it?

[flyingfudge]

https://forums.x-plane.org/index.php?/files/file/50510-popup-icing-display/

Edited February 3, 2022 by flyingfudge

[flyingfudge]

Don't know whether it's x-plane wrongly reporting ice or something to do with Toto's simulation of temp/humidity over the past 24 hours

but the problem is that there's no visual ice on the wings. Having spent considerable time setting up the aircraft to find that it won't get airborne

due to ice that cannot be evaluated visually on the walkaround completely ruins what is otherwise an amazing simulation of this aircraft.

It's the same again at a different airfield (LFLB) with clear skies and a temperature of +8C.

Are anyone else having similar problems or is something maybe affecting the icing datarefs on my system?

 

[Pils]

Have you ever seen ice on the wings in your sim? Can you force weather to be icing conditions, wait a while, and show the ice dataref output on screen (like you have FPS)?

[flyingfudge]

No problem with it showing ice sometimes. I don't know what exactly the icing numbers mean but presumably they reflect the intensity of ice being experienced on the aircraft wing.

Maybe it's just a bit of fine tuning needed to display ice on the wing at lower levels of sublimation.

However there's something not quite right as in both these cases the aircraft was unable to get airborne and climb.

In real life you have the benefit of touch but unfortunately unless it's depicted visually in a simulator it'll end up ruining your day!

Edited February 4, 2022 by flyingfudge

[Pils]

What are the ice dataref numbers for when you can’t see the visible ice?

[danhenri]

I can confirm that I had this problem too, twice. That's why I posted elsewhere a question about the precise conditions in which we may expect ice on the wings. It appears that it can occur with temperatures >0° C, with a dew point closed to the these ones. And it that case, sometimes, ice is not depicted.

Just one example : on a flight online on IVAO, actually, I had ice on the wings and ask the ATC guy to stop taxiing for de-icing. He confirmed that there was no reason to de-ice according to the weather conditions of the day. The hour of the flight was at the end of the day, not in the morning.

Just for information. By the way, I like this plane very, very, very, much...

Edited February 5, 2022 by danhenri

[flyingfudge]

10 hours ago, Pils said:

What are the ice dataref numbers for when you can’t see the visible ice?

My last but one post above with a pic. of a clean wing is showing 0.4886.

The picture above with ice depicted correctly is 0.8358

I presume these are the datarefs in question but if there are others how do I find them?

[Graeme_77]

I've submitted a feature request that the aircraft be aware of rapid and implausible temperature changes (i.e. changes that are not possible for real, and so must come from a weather engine) and uses that a trigger to update the airframe icing state. However that's not without difficulty as the result could be an unexpected change to the wing ice state. If there's a possibility I'm sure the developers will find it when they have the time, but yes for now with external weather sources just be aware of the potential for ice to be present if the Challenger sim started up in suitable weather conditions, even where a weather injection engine subsequently changed the weather.

Edited February 11, 2022 by Pils

[Graeme_77]

Issue solved, fix will be in next version.

"I've added a delay at boot before icing is applied. That should hopefully give enough time to any weather injector to come alive. I've also implemented historical METAR reading for the nearest station, which will give accurate temps and weather evolution. This mechanism is used if we detect that real weather has been configured by the user (either using X-Plane's weather, ASXP, xEnviro or XP-NOAA)."

[Jakobb]

I still have the icing issue. 

Wings used to be red but got to yellow on their own: temperature was between 5-11 degrees over the past 24h, 11 now. Rain yesterday evening

 

[beep747]

Hopefully it will be solved in the next update.