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colinm44

Feeder tanks run out of fuel after about 300 miles

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After about 300 miles the feeder tanks run out of fuel. As far as i know I have followed the checklists to a T.  Watching the needles more closely I noticed that the wing feeder tanks start off at the orange mark then slowly go down to zero at about 300 miles then the engines stop. The center tank seems ok.

Any ideas about what i could be missing?

 

I should mention that the main tanks are pretty full when this happens

Edited by colinm44
note

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I guess the first obvious question is are the transfer pumps on (no XFER yellow lights on )? And remind me please, which sim are you using?

Al

Edited by ark

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Hi Al, yes the transfer pumps are on. And no yellow lights. Im using p3d 4.5 hf3

 

And on v2.0A

 

 

Edited by colinm44

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Are all the rotary crossfeed and cross boost pump switches on the overhead panel vertical?

I had something like this happen quite a long time ago, even though all boost and transfer switches were on. That seemed to be caused by setting the Falcon as the default flight, rather than loading a standard P3D aircraft.

Edited by JRBarrett

Jim Barrett

Licensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.

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23 minutes ago, colinm44 said:

Hi Al, yes the transfer pumps are on. And no yellow lights. Im using p3d 4.5 hf3

 

And on v2.0A

 

 

Note the latest Falcon version is 2.0b. However, I don't know if that makes any difference wrt your strange fuel problem.  

 

Al

Edited by ark

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20 minutes ago, JRBarrett said:

Above the boost pump switches are three more switches for the transfer pumps. Those are switched on after engine start to start pumping fuel from the wing tanks into the feeder tanks to keep the feeders topped off. If you don’t do this, the feeders will empty, and since they feed the engines directly, the engines will then flame out.

Jim,

My understanding is that if a Xfer pump fails there will still be some reduced rate fuel transfer from a wing tank to the feeder because of bleed air differential pressure. Does this hold for the case when an Xfer pump is actually turned off as well, or is that a different story? And even with a reduced rate fuel transfer, is it likely the feeders will still eventually empty at a typical flight cruise setting because the rate of fuel transfer to the engines exceeds the reduced rate to the feeders?

Al

 

Edited by ark

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Forgot to mention that I don't have falcon as p3d default although I do have it as a saved flight. which I load up. Also, when I load falcon from a saved flight the REX environment crashes. 

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7 minutes ago, colinm44 said:

yes , all vertical. Are you suggesting I load a different aircraft then switch after its loaded?

We have found that due to the complexity of the Falcon and Lear, it is good to use the default F-35 as your default flight so it loads into the rotating preview window when you start the sim. You can then switch to the Falcon, etc. What you want to do for this is load the default F-35 onto a runway, make sure the engines are running and avionics powered up, then save it as the default flight. This seems to help with initializing sim variables. 

Until all is working I think I would delete all Falcon saved flights.

Al

Edited by ark

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24 minutes ago, ark said:

Jim,

My understanding is that if a Xfer pump fails there will still be some reduced rate fuel transfer from a wing tank to the feeder because of bleed air differential pressure. Does this hold for the case when an Xfer pump is actually turned off as well, or is that a different story? And even with a reduced rate fuel transfer, is it likely the feeders will still eventually empty at a typical flight cruise setting because the rate of fuel transfer to the engines exceeds the reduced rate to the feeders?

Al

 

There will, but I think the flow rate will be pretty low from only gravity and the pressure in the tank. The Falcon 900 is different in that there are no discrete feeder tanks, the main tanks feed the engines directly.


In the 50, if a transfer pump fails, you would open the transfer cross feed valves (in between the XFR lights), this permits any wing tank to supply any feeder tank, using the remaining transfer pumps.

I’m not sure how Mark has coded the fuel system I.e. if the cross feed valves actually function as they would in the real aircraft, or if the feeder tanks stop all replenishment from the wings with all transfer pumps off.


Jim Barrett

Licensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.

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18 minutes ago, JRBarrett said:

’m not sure how Mark has coded the fuel system I.e. if the cross feed valves actually function as they would in the real aircraft, or if the feeder tanks stop all replenishment from the wings with all transfer pumps off.

I believe the cross feeds are supposed to work. If you look at the fuel map (shift+2) as you play with the cross feeds, you will see the fuel flow, as indicated by the different colors, changes. How well that all works in flight I don't know, never tried it.

Al

Edited by ark

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10 minutes ago, ark said:

I believe the cross feeds are supposed to work. If you look at the fuel map (shift+2) as you play with the cross feeds, you will see the fuel flow, as indicated by the different colors, changes. How well that all works in flight I don't know, never tried it.

Al

I’ll have to give that a try on my next flight.


Jim Barrett

Licensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.

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I just had this issue on a flight in p3dv5.. I started the flight with the default F35 as instructed. First time this has happened to me.

 

Side note: The no AP Lights issue is still present in p3dv5 when not loading the default F35 first.


PC- i9-9900KS, 32gb 3200mhz RAM, Nvidia RTX2080Ti

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36 minutes ago, snapshot21 said:

Side note: The no AP Lights issue is still present in p3dv5 when not loading the default F35 first.

P3Dv5 seems to have a lot of bugs at this point so we will need to see how things go once the greatly anticipated Hot Fix 1 shows up (supposedly this week).

As for the AP lights, that shows the importance of starting with a relatively 'simple' default aircraft before loading a complex aircraft. The first time I saw this recommendation/warning was from PMDG when I bought their B737-800NGX for FSX a good number of years ago.

Al

Edited by ark
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Well, Al, I kind of disagree with you. You shouldn't have to do anything to get this plane moving. Loading up another aircraft before loading this one. I don't have to do this with anyother payware. As for running out of fuel after 300 miles in p3d 4.5... And as for being a complex aircraft, I think this one is old, tired and buggy and NOT as complex as newer offerings. I have uninstalled it as Im fed up with the frustration of it and moved on to a far more superior business jet and for less money. Ive lost my money but learned a lesson. Maddog, you were right.

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