"mike regish" wrote in message news:R%xtb.161414$275.497496@attbi_s53...
Two watches will do that. Or a double timer like I use.

There are a number of reasons why you might be using fuel FASTER than you
are timing it. Let me tell you a few stories.

A few years ago we got the Navion back from annual. The IA had signed off on it, and
another A&P, Margy, and I put the plane back together. The A&P and I took it up for a
test flight and after immediately opened her up to inspect for leaks and all looked good.
The next morning we take off for Oshkosh with Margy in the left seat. She's negotiating
with Approach for FF and a Class B clearance. I'm looking at the fuel guage and thinking
"I'm pretty sure I topped the thing off, but we're down gas." I tell Margy and I tell I'll keep
an eye on it. As it is, we've got over 80 gallons left on board. The downward trend continues.
Just at this time approach calls back with oru clearance. We're about midway between
two airports, we tell Dulles that we're going to Leesburg, they offer assistance.

Get down on the ground, find a mechanic, find that a fuel line is loose and spraying fuel
all over the inside of the engine compartment. I do a quick calculation and determine that
we have used 20 gallons in a 20 minute flight. That is 60 GPH!

Another long time rec.aviator put his Cardinal down on a road because he ran out of fuel
due to a higher than predicted fuel burn. Was found that his carburator was leaking.

Another rec.aviator ran out of fuel IFR. Nobody yet knows what happened, but he ran
out way ahead of what preflight planning predicted.

****ty as your average light plane fuel guages are, they are NOT superfluous.