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NoahBryant

Freezing Fuel

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One of the 50,000,000 little things I love about the MD11 is the fact that you have to watch out for your fuel freezing. However, I've done a few transatlantic flights lately and have run into a problem. Now that winter is upon us, my TAT has gone down well below -40c at about FL300 or so. At first I thought this may be a bug with my weather engine (REX) but I looked at the current upper level winds/temps and saw that YES it really is that cold up there. This has caused my fuel to freeze and my engines to shut down. When I descend to about FL250 I am able to restart them but this has left me with no option but to cruise at around FL250. So my question is if it is realistic for this to happen so fast (within about an hour of reaching cruise). I would think that it would take several hours for the fuel to get that cold with a TAT of about -50.and if it IS realistic for it to happen so fast, what is my solution?

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One way to avoid this it to use a fuel type with a lower freeze temperature. You can set this from the FUEL INIT page. Depending on the fuel type you select freeze temparture varies from -40 to -58. On this page you can also manually change the fuel freeze temperature. See FMS manual page 10.26.The rates Jon mentioned are implemented, actually the rate of change we have simulated is a bit lower (~2.0

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@Michael, would it be possible to add a fictional fuel type which never freezes or allow higher negative temperature entries than -58?This could be useful, when you do a long haul flight in real time and let the flight sim alone for a longer time. When the fuel now freezes the plane will crash because you wont notice it. Jan-Paul

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@Michael, would it be possible to add a fictional fuel type which never freezes or allow higher negative temperature entries than -58?This could be useful, when you do a long haul flight in real time and let the flight sim alone for a longer time. When the fuel now freezes the plane will crash because you wont notice it. Jan-Paul
Jan-Paul,What you can do instead, is disable wx updates and use clear weather while you are away from the sim. Michael

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Jan-Paul,What you can do instead, is disable wx updates and use clear weather while you are away from the sim. Michael
Thanks for the great replies.

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Jan-Paul,What you can do instead, is disable wx updates and use clear weather while you are away from the sim. Michael
Thats exactly the point which I want to avoide. Jan-Paul

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I have been using FS9 for years but eventhough I have had FSX for a long time I haven't been using it until now. This fuel freezing issue. Is it an FSX thing or something PMDG put into the MD-11 (I don't have the MD-11 yet)? Does it happen with the FSX 747 too? I like some others usually don't monitor my flights the whole time. Freezing fuel could cause me a problem. I too like to have real world weather. I have been an airline pilot for 12 years flying as high as 41000 feet regularly and have never has fuel temperature issues. In fact other than the British Airways 777 I haven't heard about planes have a problem with freezing fuel. I'm just trying to learn about this isue in FSX.

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I have been using FS9 for years but eventhough I have had FSX for a long time I haven't been using it until now. This fuel freezing issue. Is it an FSX thing or something PMDG put into the MD-11 (I don't have the MD-11 yet)? Does it happen with the FSX 747 too? I like some others usually don't monitor my flights the whole time. Freezing fuel could cause me a problem. I too like to have real world weather. I have been an airline pilot for 12 years flying as high as 41000 feet regularly and have never has fuel temperature issues. In fact other than the British Airways 777 I haven't heard about planes have a problem with freezing fuel. I'm just trying to learn about this isue in FSX.
It's just an MD11 issue and I 'solved' the problem by selecting a higher freeze temp for the fuel. (default is -40c)Interestingly, I only had the problem when I used the REX WX engine because it looks like ASX's weather never get's that cold. However looking at real wx info it seems that REX was correct to simulate -40 to -50 temperatures at altitude.

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This is what brought down a BA 777 a while back.
So they *think*... That report couldn't really pinpoint exactly how it happened as far as what I read.

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So they *think*... That report couldn't really pinpoint exactly how it happened as far as what I read.
The best theory they have now is the fuel heaters were not effective enough, and the fuel lower in the tank froze and could not be pumped through the system, and when the fuel level got to that point, Bam duel flame out. That was a lucky accident as it happened at low speeds close to the ground.Michael P.

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I think the single biggest factor that kept it from being worse is that there was a nice big clearway on the approach end of the runway. We had a 777 have an engine fail to repond for very different reasons at LAX which got me thinking what if the BA thing happened there. The results would have been far worse.

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