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dolin

Tank/eng

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HiExplain to me this: on long haul flights, every time I perform the tank-to-engine procedure an EICAS message appears: X FEED CONFIG. If I reverse the procedure the X FEED message disappears, but the FUEL TANK/ENG reappears.If the FMS thinks the valve position is not correct for the moment why does he tell me to perform the tank-to-engine? Though I know it's not a major failure at all, can anyone explain this to me?And another question, out of curiosity: On a real 747-400, when the autothrottle commands thrust, do the throttles follow every change of thrust after a new speed selection (for example during climb, passing from CLB-1 to CLB)?After reading the Engine section of the System manual I got a bit confused; as far as I understood the throttles won't move and the autothrottle controls thrust independently. If this is right, why is it not replicated in the PMDG 747?As always, thanks for your answers!


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Hi,Do you remember to close the two Fuel X Feed valves after you have shut down the Override Pumps? It's the only thing I can think of at the moment that can produce that message.If you are asking if the thrust levers move when more/less thrust is applied, then yes. It would move just as much as it would if you controlled them yourself.


Raymond Bergseng ENGM

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Asus P6T WS Professional, Intel Core i7 980X 3.33GHz (OC to 3.8), Zalman CNPS9700 NT CPU cooler, 12 GB OCZ Platinum XTC DDR3 1600MHz, EVGA GeForce GTX 580 "Superclocked Edition" 797MHz 1536MB, M-Audio Fast Track Ultra external USB soundcard, WD VelociRaptor 300GB SATA discs, Cooler Master Stacker nVidia Edition w/850W PSU, Dell UltraSharp 24" LCD, Windows 7 Ultimate x64, Logitech Ultra X Premium Keyboard, MX 518, Saitek Yoke and Rudder.

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This comes up every now and then, the issue normaly occurs if you have had the APU running on the ground for a while, it draws fuel from Tank 2 and causes a slight imbalance. When you get the tank to engine msg dont do anything for a few minutes then go tank to engine and it will work normally.


Rob Prest

 

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Guest 413X3

Yep just shut down the left override pump and let the right tank feed until they all balance out

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Is this just in the sim?This is interesting as I quite often do the tank to engine routine on the real jet with a small imbalance of 500kg between tanks 2 and 3 without seeing X-feed config message,the manual just says it will display with either crossfeed valve 1 or 4 closed and "main tanks not equal" ??? so taking the manual at face value I should be seeing the x-feed eicas message but never have.Thats the trouble the boeing manuals have been dumbed down a bit and dont have as many details as before,there has to be more to it ?I`m thinking that FUEL TANK/ENG eicas (tank 2 is less than 1 OR tank 3 is less than 4) will ihibit the X-FEED CONFIGWith regards the autothrottle, yes the servos move the actual throttle levers.cheersjon Bunting


747-400 captain. 

Technical advisor on PMDG 747 legacy versions QOTS 1 , FS9 and Aerowinx PS1. 

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I dont think the real aircraft behaves likes this, I'm in Bahrain on Saturday so can check this if nobody confirms it earlier. Something I have noticed, most SOPS and Airports want the APU started max 10 - 15 minutes before pushback for obvious reasons. Of course you may find yourself in a real world situation were you dont have ground power, we have the luxury of a Sim, I have never had the tank to engine issue since I only started the APU when I needed it proir to pushback.Regards


Rob Prest

 

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That is weird. I have guite a few hours in the PMDG 747-400 now and I can't really say I have seen that X feed config- message in EICAS yet. That is despite the fact that I sometimes can have the APU running for an hour to an hour and a half before departure.


Raymond Bergseng ENGM

________________________________

 

Asus P6T WS Professional, Intel Core i7 980X 3.33GHz (OC to 3.8), Zalman CNPS9700 NT CPU cooler, 12 GB OCZ Platinum XTC DDR3 1600MHz, EVGA GeForce GTX 580 "Superclocked Edition" 797MHz 1536MB, M-Audio Fast Track Ultra external USB soundcard, WD VelociRaptor 300GB SATA discs, Cooler Master Stacker nVidia Edition w/850W PSU, Dell UltraSharp 24" LCD, Windows 7 Ultimate x64, Logitech Ultra X Premium Keyboard, MX 518, Saitek Yoke and Rudder.

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I have run into this too, if all the tanks are equal, then shutting off the xfeeds and the overide pumps clears the message. But if you have a few hundred pounds difference, doing the same will give a X-FEED CONFIG error, but if you switch back, you get the TANK/ENG message. I have balanced out the tanks manually by shutting down the pumps pulling fuel out of the lighter tank and having the other side main fuel the whole airplane for a few mins. Then it's OK. But, if you dont have this much time to spend on this, at the point that the TANK/ENG message appears, go into the PMDG options menu and it should have in the amount the exact amount you are running in the aircraft. Click on apply, then it reconfigues itself instantly, shutting off all the OVRD tanks and cross feeds and you will have equal fuel everywhere you should have it. It's a cheat, I know. But an effective one!


Bill Howard

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Guest 413X3
That is weird. I have guite a few hours in the PMDG 747-400 now and I can't really say I have seen that X feed config- message in EICAS yet. That is despite the fact that I sometimes can have the APU running for an hour to an hour and a half before departure.
The only thing I can think of is you can't be doing flights longer than 4-5 hours

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I dont think the real aircraft behaves likes this, I'm in Bahrain on Saturday so can check this if nobody confirms it earlier.
Hi Rob, no you`re right it doesnt. The only time I`ve seen the X-FEED CONFIG eicas is when you first get on and the fuel panel hasn`t been configured, ie its been refueled and the panel has been left in tank-eng config from the previous sector. Our fleet has recently been developing a small imbalance of less ,1000kg between 2&3 for some,as far as I know, unknown reason,so I quiet often go tank to engine with the imbalane and tank 3 has more in it than 4 at the time of tank to engine but it still doesnt bring up the X-FEED CONFIG eicas.I susspect the tank to engine eicas once triggered would inhibit the x-feed eicas, at least inthe air.Looks like this is a "sim-ism"CheersJon

747-400 captain. 

Technical advisor on PMDG 747 legacy versions QOTS 1 , FS9 and Aerowinx PS1. 

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As I'm mostly flying the freighter version of the 747, 4-5 hours flight as an average sounds right.However, a couple of days ago I had an 8 hour flight. Because of the APU I had running before departure, I had around 600 kg imbalance in tank 2 during the entire flight. I did not get any x-feed config message at all. I wonder where this limit goes to get this message? :(


Raymond Bergseng ENGM

________________________________

 

Asus P6T WS Professional, Intel Core i7 980X 3.33GHz (OC to 3.8), Zalman CNPS9700 NT CPU cooler, 12 GB OCZ Platinum XTC DDR3 1600MHz, EVGA GeForce GTX 580 "Superclocked Edition" 797MHz 1536MB, M-Audio Fast Track Ultra external USB soundcard, WD VelociRaptor 300GB SATA discs, Cooler Master Stacker nVidia Edition w/850W PSU, Dell UltraSharp 24" LCD, Windows 7 Ultimate x64, Logitech Ultra X Premium Keyboard, MX 518, Saitek Yoke and Rudder.

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I was interested to see Bill Howard's remedy. I will try that one. I do a lot of long haul flights 10-12 hours and seem to get the Tank/eng message a lot, even though the tanks are in fact balanced. I seem to often fly the last few hours with the Tank/eng warning and now used to it....I always use the APU at start-up and by the time I have put in the flight plan, my fuel tanks are always out of balance. I usually shut down the relevant pump so I run down the fuel in the offending tank until it balances and the Tank/eng message mostly goes out. Regards


Geoff Bryce

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