NoSpam wrote:

Is there a way to accurately measure the fuel in the tanks while the aircraft
is on the ground (using some "mechanical" measuring tool/gauge)?

Yes. Make or buy some sort of dipstick. Mine is a clear plastic tube. I bought it
and drained one of my fuel tanks. We then pumped in 5 gallons and marked where the
level was when I stuck the tube in. Put in another 5 gallons and marked that. And
so forth. Now I can stick the tube in the tank, pull it out, and know within a
gallon or two how much is in that tank.

Is there a way to
accurately measure the amount of fuel in the tanks while in flight?

No. As others have stated, use your watch and the gauges. Whichever indicates the
least amount of fuel is what you "believe". Land if you even think you *might* be
getting low.

George Patterson
Great discoveries are not announced with "Eureka!". What's usually said is
"Hummmmm... That's interesting...."