Engine Behavior in Severe Icing Conditions
I was doing some testing today and observed something I was very happy to see (as a virtual pilot who loves cold weather operations for some reason...).
Conditions
- Ground Operation
- Severe Weather (Sub zero temps, dense snow fall)
- No deicing operations
Observations
- Neither engine would start; I could get roughly 30 RPM on the props but the engines would not light off. This was with the engine intakes in the closed position.
- After opening the intakes, both engines started fine
- I closed the intakes, and ran the engines for about 15-20 minutes while multitasking. Came back to the sim and they were dead
. - I opened the intakes, restarted both engines, closed one intake and that engine died in about 5-10 minutes.
From what I read in another thread, I'm assuming what happened is the intake clogged with snow and the engine died due to insufficient intake air. Is this correct?
Comments
Let yourself be de-iced before the engine starts.
The engine intake bypass doors can be opened after Engine Start up below 25 ° C, the heaters work from 15 ° C and lower.
Most operators leave the intakes open also to allow FOD ingested during normal ops like bird strikes.
We have modeled the engines so that when sitting in sub zero temps and or snowy conditions, the engine inlets get built up snow and ice, resulting in reduced engine performance. Performing engine deicing procedures before leaving the gate is the required thing to do. As the ice build up on the wings and props will also be noticeable if departing with a non clean aircraft.
Krosswynd said:
"Performing engine deicing procedures before leaving the gate is the required thing to do"
Hi,
I know that through the FMS we could initiate the deicing procedure but if we use only GSX deicing does it gives the same result or is it only a "visual effect" with no effective deicing. Also could you be good enough to let us know howlong after the deicing procedure is finished (through the FMS) is it effective.
Thanks and regards,
JP
Isn't it also the case that the Engine Intake Heaters / Bypass Doors are controlled by 2 control systems, whereby one system always controls both? The change from system 1 to 2 is done on the ground by opening and closing the bypass doors with the appropriate switches. If you do not do this because the bypass doors are constantly open, the control unit will not be changed and only one will work.
The deicing of the same can not be a prerequisite for the start of the Engines, because there may be separate deicing areas at airports to which the aircraft must first roll, i.e. not always de-iced directly at the gate or at the parking position. Nevertheless, a nice feature that forces you to take external conditions into account in the preparation.
If you read the manuals again, the simulated de-icing in the FMC seems to relate to checking and clearing the engine intakes, which is mentioned in the Cold Weather Operations.
Yes but my question is relating to GSX and if we de-ice through GSX does it give the same result on the engine intakes knowing that with GSX we can de-ice only at the gate/parking before starting the engines?
If that were the case, one would of course also have to ask about AES. I don't think so, because, as you could read, the performance data of the aircraft are affected. I would doubt that this comes from AES or GSX.
OK Thanks. I am not really surprised as I believe that the de-icing is done internally in the aircraft profile. So if we want to have it realistic we use the de-icing through the FMS and we play the de-icing scenario through GSX to have it visually.
The other question was how long does the de-icing efficiency last with the MJC Q400.
As you know in RL, of course depending of the weather conditions, it could be efficient for 10 to 20 minutes.
This depends not only on the external conditions, i.e. type of impairment (snow, ice, moisture, temperature, ...) but also on the fluid type used and is a science in itself. I think in FS the whole thing with de-icing via FMC is enough before starting the engine, because de-icing via GSX / AES can only be used by those who have these add-ons.
> Krosswynd said:
>
> "Performing engine deicing procedures before leaving the gate is the required thing to do"
>
> Hi,
>
> I know that through the FMS we could initiate the deicing procedure but if we use only GSX deicing does it gives the same result or is it only a "visual effect" with no effective deicing. Also could you be good enough to let us know howlong after the deicing procedure is finished (through the FMS) is it effective.
>
> Thanks and regards,
>
> JP
So technically once you have been deiced there is a time limit for which the hold over time will expire, I am not quite sure whet the time limitation is before one would have to redeice. I think we may have held off on putting a realistic time as this may have cause some frustration for users at large airports exceeding with taxi times exceeding 15 to 30 min.
During our SC flights, the boss and I have used gsx for deicing has testing was conducted to allow for both.
There are still some areas that need fine tuning.
Cheers
Thank you to both of you.
Thank you FraPre for the info regarding the Q400. I have heard that today the de-icing is done with different fluids. In the ancien times when I was flying there was only one fluid which was a mixture of glycol and water and on the windsceen we were using more or less pure alcohol. No we did not try with Gin !!!
Thank you Simeon for this info as it would make the flights more and more realistic especially that I am doing a bit of flying presently in Sweden and Norway.
Regards,
JP
Thanks everyone for the info,
I was sharing my observations in hopes that others who are interested in cold weather operations could see what I've observed. The feedback has been very helpful - and hopefully, anyone doing pre-purchase research on features (like I tend to
) will find this helpful as well.
The level of detail in the Q400 is incredible - thank you Majestic SW team!! I'm looking forward to the training version.
I hope everyone has a great holiday season - Matt.