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Virgin_A340

Oil Pres Low MD11

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I had a problem with loss of airspeed on my last MD11 flight but thought it was due to wind problems. I just redid the exact same flight but watched the controls/displays all the time this time. At exactly the same point as I lost speed last time I got a "Oil Pres Low" in yellow on the display. All engines then lost all power and my speed dropped so much that I could not fly any more. I checked that all the fuel levers were still in and they were so that's not the problem. I have no idea what caused it and it's strange that it happen twice and in the same point on my flight. Anyone know anything about these issues?Cheers,Andy S

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I had a problem with loss of airspeed on my last MD11 flight but thought it was due to wind problems. I just redid the exact same flight but watched the controls/displays all the time this time. At exactly the same point as I lost speed last time I got a "Oil Pres Low" in yellow on the display. All engines then lost all power and my speed dropped so much that I could not fly any more. I checked that all the fuel levers were still in and they were so that's not the problem. I have no idea what caused it and it's strange that it happen twice and in the same point on my flight. Anyone know anything about these issues?Cheers,Andy S
Did you check your Fuel Temps?

Rob Prest

 

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Did you check your Fuel Temps?
No I didn't check that. If it was fuel iceing how would I stop it happening? I mean I had everything on auto so I don't understand how it would freeze. Plus I've never had that problem with any other PMDG product or any other add-on for that matter.
are you using any programs like REX 2?
I was using Active Sky v6.5, FS Real Time, Ground Environment, AI Smooth, Radar Contact and an ACARS programme for my virtual airline. I also have FSUIPC registered version and have all the wind and pressure smoothing set.

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If it was fuel iceing how would I stop it happening?
Go to warmer air, usually lower.
I had everything on auto so I don't understand how it would freeze.
There's no "automation" to prevent it, the fuel eventually becomes about the same temperature as the TAT. You have to keep an eye on that in colder air. Check the manual, the temps for a couple of fuel types are there and you have the option of fueling with a lower fp fuel. I don't recall the details.

Dan Downs KCRP

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No I didn't check that. If it was fuel iceing how would I stop it happening? I mean I had everything on auto so I don't understand how it would freeze. Plus I've never had that problem with any other PMDG product or any other add-on for that matter.
The MD-11 will at some point start to pump fuel around to slow down its cooling process. If that is not enough you have to descend to a lower level and/or increase speed to increase TAT. Now if you KNOW that the air is going to be extra cold at cruise you're welcome to use another type of fuel with a lower freezing point.You might not have seen this in another add-on so far because most of them do not simulate the consequences of fuel freezing.Regards,Markus

Markus Burkhard

 

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I was only nearing FL380 and hadn't reached my cruise alt (FL380) when all this happened. Is it likely that the fuel would have frozen that quickly? This was only about 20 miuntes max after takeoff. According to Active Sky the air temp would have been between -50.4 and -51.2.Andy S

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I was only nearing FL380 and hadn't reached my cruise alt (FL380) when all this happened. Is it likely that the fuel would have frozen that quickly? This was only about 20 miuntes max after takeoff. According to Active Sky the air temp would have been between -50.4 and -51.2.
Andy,the fuel shouldn't freeze up that quickly you're right. Can you observe the situation a bit more in detail should this happen again and/or provide us with screenshots?Markus

Markus Burkhard

 

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You could also change the fuel type from A to B in the MCDU as B has a lower freeze temperature
I just did that and I am currently past the area where I had the problems the last two times. Fingers crossed!

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I just did that and I am currently past the area where I had the problems the last two times. Fingers crossed!
Just after I said that....crash. I went back into the sim and the MD11 was at about 1000ft with a overspeed. The screenshot tool decided to pack up to so I couldn't take any shots. Anyway I noted that the fuel was at -4 deg, I got Engine Pres Low yellow warnings and the engine pressure was at 500 but had been normal up to then. Apart from the overspeed warnings everything else was as it should be.

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So the fuel temp is ruled out. What screenshot tool? I just press the PrtScrn key, open default Paint to resize 80% to meet forum size limits and save as jpg to desktop. A screenshot would cut down the number of questions and answers to find out what is happening.What is going on with the overspeed? Are you getting unrealistic wind shifts? Only registered copy of FSUIPC can fix those, AS6 can't handle it.


Dan Downs KCRP

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So the fuel temp is ruled out. What screenshot tool? I just press the PrtScrn key, open default Paint to resize 80% to meet forum size limits and save as jpg to desktop. A screenshot would cut down the number of questions and answers to find out what is happening.What is going on with the overspeed? Are you getting unrealistic wind shifts? Only registered copy of FSUIPC can fix those, AS6 can't handle it.
At the risk of sounding repetitive... :( This condition is also caused by bad barometric pressure at cruise altitude. I encountered it on multiple occasions with AS. The erroneous pressure causes the engine model to not be able to generate enough thrust to maintain altitude. While your original problem looked like a low temp, seems like you were having two issues. The only way I know how to fix this is to turn on FSUIPC barometric pressure smoothing functions and limits. Once I turned it on, the issue was resolved.

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At the risk of sounding repetitive... :( This condition is also caused by bad barometric pressure at cruise altitude. I encountered it on multiple occasions with AS. The erroneous pressure causes the engine model to not be able to generate enough thrust to maintain altitude. While your original problem looked like a low temp, seems like you were having two issues. The only way I know how to fix this is to turn on FSUIPC barometric pressure smoothing functions and limits. Once I turned it on, the issue was resolved.
I have the registered version of FSUIPC and have barometric smoothing on. Along with all the wind smoothing etc that has been posted in these forums. I thought it was a wind problem at first but I am not convinced it's not.PS - MODS should this not be in the MD11 section of the forum? :( Andy S

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Same Problem for me. It allways happen to me directly after takeoff or directly before landing. No difference wich fuel type i take. Im using REX 2 but tryed it also with FSX standart clear sky weather. I also use a registered version of FSUIPC with barometic smoothing on but still the same. The Plane is absolutly correct configured.So my daily flight is allways:fire up my MD11taxistart and then yellow boxes:eng1, eng2, eng3 oil pres lo and i fall down like a stone....Pls help :(Frank

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