In article , Michael wrote:
The reality is that we have a dumb way of dealing with fuel. We use
the clock. It's dumb because it assumes we know the fuel burn and
that nothing is leaking. Too many assumptions, too easy to go wrong.
What we need are accurate fuel gauges that are cheap enough to make
retrofits sensible. As long as they have to be FAA certified, that
won't happen.

Fuel gauges in many planes *are* good enough, though. There are some
that are terrible (I've never flown a C172 with a fuel gauge that was in
any way useful), but many are fine. The trouble is (especially with old
planes) you have to fly them a few times and check the fuel gauges to
get any idea of whether they are any good.

My old C140 had mechanical fuel gauges. They were very accurate. Other
planes I've found good fuel gauges in - Grumman Tigers/Cheetas, the old
1960 C182 we had in the flying club, Beechcraft (both the Bonanza and
Musketeer I've got to fly had fuel gauges that were worth something).
The fuel gauge in the Auster I tow gliders with is very good. It's a
cork with a little stick indicator on which protrudes out of the top of
the fuel tank!

I don't just use time, I also monitor the fuel gauges. A good job too -
when I was new to our club's old C182, I *thought* it was full of fuel
(visual inspection showed less than an inch between the liquid and the
filler, which was full for my plane). Since it only had 55 gallon tanks,
it's not hard for a cross country to be the full IFR range.

My usual practise is to time AND check the gauges. If the fuel gauges
show less fuel than I think I should have, it's a cause for concern. On
this particular flight, I noted that at the point I should have had half
a tank, I had 2/3rds of a tank indicated on the fuel gauge.
Either the gauges were wrong, or I didn't have as much fuel as I should.
I elected to land at the next airfield to check it out.
Good job too - I had about 45 minutes less fuel than I
thought I really had when I left. If I had pressed onto my desired
destination just using my stopwatch as a fuel gauge, I would have
arrived with about 10 minutes of fuel remaining. Diversions, holding, go
arounds etc. could have easily eaten that in its entirety.

Of course, before takeoff, the gauges were on the 'F' marking, but I
discovered after topping off the tanks at my diversion field that 'F'
isn't really quite full - it's full when the gauge points well past full
(like many car fuel gauges). That last inch was in fact about 10
gallons!
--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"