1. Fuel required for flight. I know the approximate range of the aircraft I regularly fly. If my flight is going to be at least 2 hours less than the fuel I'm carrying, I don't bother working anything out. Otherwise, get out a plog (the chances are it's a long enough trip that I've done a full plog anyway) and work it out more accurately.
2. In the Europa - the fuel guage is a capacitance-type guage, and so is pretty reliable. There is absolutely no other way of checking the fuel, so I have to rely on the guage. I have about an hour in the reserve tank in case the guage turns out to be faulty and it all goes quiet. In every other aircraft I've ever flown, I check the fuel visually before I fly.
When I uplift fuel, I always fill the tanks to the top - this avoids any doubt about how much fuel there is. Two exceptions are when weight+balance is an issue (I fill to my w+b limit, minus a bit in case I eat too many pies at my destination), and refuelling the Europa at the end of the flight (group policy is to re-fuel to the 3/4 mark on the fuel guage to ensure the next pilot doesn't have a w+b problem).
3. Check the guages regularly (every 15 mins or so). Check that they read roughly what I'd expect them to read at this stage during the flight. There's not much more you can do, is there? If I have multiple fuel tanks to choose between (a la PA28), I usually change tanks every 30 minutes or so. Most of the trips I've done in this type of aircraft, there's been enough fuel in either tank to last the entire journey, so if I screw up en-route it doesn't really matter. I've done a couple of longer trips - a 400nm trip in an Arrow where I had to change fuel tanks several times springs to mind - where I've noted down the time and which tank I've selected each time I changed tank, so that if there was any confusion about how much fuel was remaining later in the flight I'd be able to work it out. But it's rare for me to fly the kind of trip where this is necessary.
Very good thread subject - interesting to see how others' habits vary from mine.
FFF
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