Lancair ListServ,

FWIW:  In my Lancair IVP, I have VMS fuel capacitance probes (AC output) which interface with Pricnceton Electronics Interface units (AC in, DC out) which communicates with my Chelton's EAU (originally made by GRT).

 

I recently re-calibrated my fuel probes output through the Princeton interface unit, as I wondered about calibration drift after six+ years.  Each tank holds 55 gallons, and the step-reading system is based on 10% increments.

As you can see, the output reading has changed over time, resulting in a display error in fuel volume in the tank.  This explains the calculated Totalizer mismatch (and WARNING message) with the probe's Fuel Quantity reading, as occassionally seen on long flights.  An example is when there was actually 44 gallons in the tank (ex, after using 11 gallons per fuel flow sensor), the older fuel map told me there was 38.5 gallons...you can understand the Totalizer error created by this.

I simply post this in case others find it relevant or interesting.

Jeff L in New Jersey

LIVP