Went out to run some errands with the Queen flying and got sidetracked. When I finally got back, I had exhausted fuel in Tanks 2 & 3 and was running all 4 engines on tanks 1 & 4. I had never tried that, and was gratified to know that things still kept running with this abnormal configuration. when I landed, was unable to start APU due to no fuel in Tank 2. Documentation mentions fuel transfer switches that allow fuel transfer from 1 & 4 to 2 & 3, but I can find no switches to do this. Is this feature not modeled in the aircraft at present?Thanks,Larry Jasmann

There is no way to tranfer fuel in the Queen. The only way to do so is on the ground by the ground/refuelling crew which is not modeled in the sim.The switches mentioned are the X-feed switches to allow fuel passage between the tank and different engines, not tank to tank.

In the real aircraft there is another overhead panel that is aft of the overhead one you see in the sim. This panel has a few additonal switches on it as well as the circuit breaker panel. One of these switches is called Main Tank 1 and 4 transfer. This switch opens up some valves between tanks 1 and 2 and 4 and 3. It allows fuel to transfer by gravity from tank 1 to 2 and from tank 4 to 3 down to a min level of 3200 kg. This system is normally used by the jettison fuel dump system. I have never heard of it being used by anyone in flight and I am not sure of the system requiremnents for it's use outside a jettison scenario but I guess it is thoertically possible, should one find themselves in a situation such as yours, to give it a go. CheersSteveEdited: for spelling errors

I was under the impression that the Main Tank 1 and 4 Transfer system was not modelled on the PMDG 747.

"I was under the impression that the Main Tank 1 and 4 Transfer system was not modelled on the PMDG 747."Which is exactly what Steve said ;)In theory (haven't tried in in real life or in PMDG), you should be able to feed the APU with fuel from the #1 and #4 tanks by switching on one of the boost pumps in those tanks and opening up the crossfeed valves.Any volunteers to test this theory? :-lolCheers.Q>

"This panel has a few additonal switches on it as well as the circuit breaker panel. One of these switches is called Main Tank 1 and 4 transfer."Correct.... and as coincidence would have it, I tried to use this switch to transfer fuel from the outboards to inboards for maintenance purposes on one of our 744's yesterday. Unfortunately, it didn't work all that well, perhaps because the levels were pretty much the same in each tank (or perhaps the levels of fuel in the outboards were not high enough to reach the transfer inlets). I had to resort to using the wing fuelling station controls to transfer fuel.Note to other engineers and pilots... before you push the (guarded) switch... make sure you have the right one. The cargo fire bottle switch is only a few inches below it.... ALMOST pushed the wrong button :-PCheers.Q>

In the Sim, with all of the cross feeds open, and all boost pumps on (excluding center tank of course), all 4 engines ran fine from tanks 1 & 4, but the APU would not start.Larry Jasmann>"I was under the impression that the Main Tank 1 and 4>Transfer system was not modelled on the PMDG 747.">>Which is exactly what Steve said ;)>>In theory (haven't tried in in real life or in PMDG), you>should be able to feed the APU with fuel from the #1 and #4>tanks by switching on one of the boost pumps in those tanks>and opening up the crossfeed valves.>>Any volunteers to test this theory? :-lol>>Cheers.>Q>

Here's a diagram showing the path of the fuel to the APU from, for example, the #1 Tank ...http://forums.avsim.net/user_files/161165.gifStart at the "X" and go to the "Y"Cheers.Q>