Neil Gould wrote:

I question this scenario as you've presented it. As you've pointed out,
the weather plays a large part in fuel burn over a distance. Landing your
plane with 30 minutes reserve fuel presumes that when you've travelled x.y
hours at a particular burn rate, the airport is right under you. Chances
are good that will not be the case, and you will wind up with either more
or less than 30 minutes fuel remaining.

Well, that's why you would need multiple "continue on or land to
refuel" checkpoints for such flight. With a GPS, it's fairly easy to
tell at multiple points enroute whether you're ahead or behind.


Also as you've pointed out, another consideration is that accurate leaning
is important to precise fuel burn. However, as GA mixture controls lack
precise calibration, one of the few other ways to know your fuel
consumption would be with a fuel flow meter. Many planes are not so
equipped, and if the plane you fly is one of those, then it doesn't really
matter whether you own it or not; you're making a guess about the
precision based on past experience, possibly against RPM.

If you own a plane with all cylinder EGT and have many hours in it,
it's not hard to fly a fuel burn rate to a tenth of a gallon, even
without a fuel flow meter. I'm sure many plane owner can attest to
that.



Lastly, how much fuel should be remaining at your destination may be
better determined by how much additional fuel might be needed if there is
some unexpected problem at the destination. I wouldn't want to have 30
minutes remaining at the destination if the alternative is 45 minutes
away. ;-)


well, if the an alternate runway is more than even 15 minutes away,
it's obviously not a candidate for such flight! See my original post
about alternate runways on the flight planning.