Turbine Duke fuel pumps
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Hello.
I have a question, that is lighthearted in nature, with regards to the fuel pumps on the Turbine Duke. In the “Before starting engine” checklist, it says to “check” all four fuel pumps, but it doesn’t specify what passes as a check. As a comparison, the equivalent passage in the Piston Duke checklist tells us that the boost pumps should be “audible”.
In the Turbine Duke, I tend to look for an increase in fuel pressure, when I check the fuel pumps, but I have noticed something curious. Both wing pumps, and also the left aux pump increase the fuel pressure enough, to extinguish the corresponding FUEL PRESS annunciator light. However, while there is an increase in fuel pressure when the right aux pump is running, it is never enough to extinguish the FUEL PRESS warning. I have checked to see that there are no active failures. It doesn’t matter either how much fuel is in the tank, for example, it won’t extinguish the light.
According to the manual, the FUEL PRESS annunciator light illuminates when the fuel pressure is <5 PSI. When running the right aux pump, the fuel pressure guage shows exactly 5.0 PSI. I thought it might be due to a weird rounding error in MSFS 2024 (stranger things have happened), but it’s the exact same behavior in MSFS 2020.
The checklists for the Caravan and the TBM both state that their respective fuel pressure lights should be extinguished, when running the fuel pumps, but, unlike the Duke, both of them should have their fuel pumps running, while starting the engine.
So, is the FUEL PRESS light supposed to be extinguished, in the Turbine Duke? Or does it not matter, as long as there is some fuel pressure? I might also add that it’s never been a problem starting the engine or keep it running. It’s more that I’m curios.
All the best.
