X-Fer Pump fail

[rennman 4]

Hi...When the fuel level gets to about 25%...I get warnings that L Xfer pump fail and R Xfer pump fail.

I didn't see fuel management in the docs...

Any ideas?

Thanks.

[whamil77 183]

The way the real airplane works is this.  There are motive flow ejector transfer pumps in the main fuel tanks that fill a "hopper tank".  Fuel from the hopper tank is fed to the engines.  If the fuel level in the hopper tank falls below approximately 80 pounds, the Xfer Fail warning will illuminate.  That figure increases to 580 pounds if the main and auxiliary boost pumps are off. 

Here's the code from the Alabeo C441:

    <Element id="Gauge_Anum_L_LXFER_PUMP_FAIL">
    <FloatPosition>0.000,0.000</FloatPosition>
    <Visibility>
    (A:FUEL LEFT QUANTITY,gallons) 9 &lt;
    (A:GENERAL ENG FUEL PUMP SWITCH:1,bool) 0 ==
    (A:FUEL LEFT QUANTITY,gallons) 87.5 &lt; and or
    </Visibility>(* less 80 pounds + boost pump off or less 850 pounds + boost pump off *)    
        <Image id="Image" Name="Gauge_Anum_L_LXFER_PUMP_FAIL.bmp">
        <Transparent>True</Transparent>
        <Bright>false</Bright>
        </Image>
    </Element>

Assuming 6.8 pounds per gallon of jet fuel, the numbers should have been 11.75 gallons and 85.3 gallons respectively, but the functionality is correct. 

http://www.cessnaconquest.net/25/17.html

[rennman 4]

does this mean i need to make sure the boost pumps are on to keep the warnings off?

 

thank for responding...

[whamil77 183]

Yes.  According to the Alabeo 441 checklist, the boost pumps are turned on prior to takeoff and turned off after shutdown.  It makes sense because without the pumps running the hopper tanks would not fill once the fuel level in the main tank got below the lip of the hopper tank. 

[rennman 4]

thank you so much for taking the time to help...im flying the 441 around the world right now...