doubles.) So the entrapped air would now
displace 16 gallons of fuel rather than the 8
it displaced at sea level, and an additional
8 gallons would have been expelled out the
right wingtip fuel vent in-flight.
Under this scenario, the not-yet-selected
right fuel tank would contain not 40 gallons (its assumed capacity) or even 32 gallons (what it probably actually held on the
ground), but only 24 gallons. Total usable fuel
becomes not 78 gallons or even 70 gallons, but
62 gallons—almost exactly the calculated fuel
burn from Ada to 2 miles short of Flagstaff!
The accident airplane was equipped with
both fuel gauges and a digital fuel totalizer.
However, the fuel gauges were inoperative
(Tony knew this), while the totalizer was
working fine. It’s reasonable to assume,
therefore, that Tony knew precisely how
much fuel he’d burned, but had no way of
telling directly how much fuel was left in
the tanks. Without working fuel gauges, he
could not have detected the postulated in-flight loss of fuel.
After the engine quit, Tony apparently did
exactly what you or I would have done in
his situation: He turned the electric boost
pump on “high” (that’s where the switch
was found in the wreckage) and tried
switching tanks. When this failed to bring
the engine back to life, Tony made a remarkable forced landing in a very small clearing, reportedly half the size of a football
field. The composite cabin structure of the
pressurized Lancair remained remarkably
unscathed and intact.
Why didn’t Tony survive the forced landing? Post-crash investigation suggests that
Tony was not wearing his shoulder harness
at the time of the crash, and on impact he
wound up splitting his head open on the
instrument panel. In a final tragic irony,
there may be a very good reason that he
wasn’t wearing his shoulder harness: It was
not equipped with an inertial reel, and it was
reportedly impossible for the pilot to reach
the fuel selector without first unbuckling the
only happens “to the other guy” because he
(or she) just wasn’t paying attention. None of
us would ever do anything as dumb as running out of fuel, right?
Tony’s accident provides a vivid counter-example. Here was a professional pilot, an
ATP and CFI with four decades and countless
hours of flying experience, who also turned
out to be a renowned expert on the type of
airplane he was flying, and even had lots of
hours in the particular aircraft involved. He
topped the tanks before takeoff. His preflight
planning was unimpeachable. His only real
sin was believing that his tanks actually held
what the book said they should hold.
When was the last time you had your airplane defueled and then recorded precisely
how much fuel it took to top off each tank?
I know, I know—you don’t fly a Lancair,
and your 1968 Skylane has fuel bladders,
not integral tanks. But it’s even easier for a
bladder tank to have less-than-book capacity than for an integral tank. All it takes is a
disconnected snap that allows the bladder to
collapse partially in the wing bay, or an industrious mud dauber who decides your tank
vent looks like prime residential real estate.
instrument or one technique. The clock and
fuel-flow gauge (which is essentially a poor
man’s totalizer) do indeed provide the primary method of keeping track of fuel used, but
the fuel quantity gauges provide an essential
cross-check by measuring actual fuel remaining. If there’s any disagreement, I will trust
whichever method (clock, totalizer, or fuel
gauges) gives the most pessimistic answer,
and make plans accordingly (including landing short of the planned destination if there’s
even the slightest doubt about fuel reserves).
Of course, if you’re going to use your fuel
gauges as a cross-check, then they actually
have to work—and they have to be reasonably well calibrated. Actually, it’s not terribly
important for the fuel gauges to be anywhere
close to accurate when the tanks are full,
so long as they’re in the ballpark when the
tanks are approaching empty.
“THE ONLY FUEL GAUGE THAT
MATTERS IS THE CLOCK.”
TO WHICH I SAY, “BALONEY!”
No matter what sort of fuel system you
have, it’s absolutely crucial that you know
the actual capacity of each tank, and that you
recheck it on a regular basis to make sure
something hasn’t changed.
It’s easy to blow off these accidents as avia-
tion’s most unforgivable sin—something that
How many times have you heard a CFI say
something like this: “Ignore the fuel gauges.
They’re notoriously inaccurate, and basically
worthless. The only fuel gauge that matters
is the clock.”
To which I say, “Baloney!” What if your
fuel capacity isn’t what you thought it was
because you’ve got a collapsed bladder or a
plugged vent? Or what if something has caused
a bunch of fuel to siphon overboard in-flight?
How accurate a fuel gauge is your Rolex then?
Mike Busch, EAA 740170, was the 2008 National Aviation
Maintenance Technician of the Year and has been a pilot
for 44 years, logging more than 7,000 hours. He’s a CFI
and A&P/IA. E-mail him at firstname.lastname@example.org.
Mike also hosts free monthly online presentations as part
of EAA’s webinar series on the first Wednesday of each
month. For a schedule visit www.EAA.org/webinars.