Running dry?

Not quite-

Did you drain the tank from the sump, or from the line? The Super Cub
is supposed to have 17.4 gallons usable, 18 gallons total. If drain it
from the sump, and fill it, you'll put 18 gallons in. If you run a
tank dry, you'll put 17.2 in. If you're running at a low cruise, that
1.6 gallons you don't have is 20 minutes of fuel that you were counting
on.
..

"Marc J. Zeitlin" wrote:

Jay wrote:

Although this thread *does* answer a question that has bugged me for a
very long time. I've often wondered how it was possible that so many
NTSB reports ended with "fuel exhaustion" as an explanation.

Now I know.

I don't really think that you do. As I noted, I can run a tank dry and
have anywhere from 2.5 to 5 hours of fuel (depending on how fast I want
to go) left in the other side - that's hardly a "fuel exhaustion"
danger - some airplanes don't carry that much fuel when they take off
full.

Marc J. Zeitlin

I have to agree with Marc on this. I know very accurately how much
fuel I have since I have run the tanks dry to "calibrate" my fuel
gauge (and engine monitor fuel gauge). And yet the closest I have
ever gotten to fuel exhaustion is about one hour of fuel remaining
with several airports between me and my final destination.

I will have to check that one hour number since I did make a fuel stop
in La Junta because my projected remaining fuel in COS was
unacceptable low (about 45 minutes between LHX and COS).

Frankly Jay if you do not wish to ever run a tank dry that is your
decision. I am not critical of it. However, I do not agree with your
assertion that running a tank dry implies the same sort of situational
awareness that leads to exhausting all fuel in flight and making an
off airport landing/crash.

Ron Lee

On Thu, 18 Aug 2005 15:42:31 GMT, "Jay Honeck"
wrote:

IMHO, proper fuel management means never even coming *close* to running a
tank dry, let alone doing it intentionally.

And how do you know how much fuel you really have in your tanks?

It seems simpler, and safer, to figure this out by running the tanks dry,
at least once, than to trust the manufacturer's numbers. In my case, I
have about four gallons less than the published numbers which is 1/2 hour
at economy cruise which is VFR reserves.

I don't see any reason to run tanks dry routinely, but my usual flights
don't require maximum endurance. Doing it once (or twice with two tanks)
seems to me to be a prudent thing to assess fuel capacity.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

"Jay Honeck" wrote
In fact, I would never have guessed that this kind of a hair-brained
"fuel management" procedure would merit a serious discussion in these
newsgroups. To even contemplate running a tank dry in the air, let
alone propose it as a standard -- even beneficial (?!) -- procedure,
makes for astonishing reading.

Jay, during a period of "shore duty" in the Navy, I had the misfortune
to ocassionly fly the SNB (Secret Navy Bomber) known to civilians as
the Beachcraft D-18. It had no electric fuel pumps, but rather a
mechanical "wobble" pump located on the floor between the pilots.

It was standard procedure to run each tank dry. When the engine quit,
the pilot switched tanks and started pumping the wobble pump like crazy.
Never had a problem.

I find that many of your posts are colored by the limited types of
aircraft that you have flown and the limited conditions under which
you have flown those aircraft.

Bob Moore

In article , Ron Lee wrote:

...I have to agree with Marc on this. I know very accurately how much
fuel I have since I have run the tanks dry to "calibrate" my fuel
gauge (and engine monitor fuel gauge)...

That's one way to calibrate the gauge. Perhaps since my Pitts has one tank I
simply drained and refilled it on the ground. The fuel flow gauge is
now accurate to a tenth of a gallon every time I refill.

Jay, you were in the newspaper biz too long to use "always", "never", and
words of that finality in your thinking.

Would I teach running a tank dry to a student? Most likely not. Would I
recommend the procedure be taught on a BFR? Most likely not. Would I run
one dry with trees, rocks, or water underneath (say, from Scottsbluff to
Sacramento)? Most likely not.

Would I run one dry where there are nothing but airports and soybeans
underneath? I might. Depends on what I'm trying to accomplish. I think
Deakin knew what he was talking about and expected at least a MODICUM of
intelligence on the part of his readers.

Let's think about why an engine would not restart with one dry. The only
reason I can see for this happening is if the fuel flow from the full tank
could not get to the engine. Air bubble? Not with any sort of positive
pressure. Fuel handle snap off in your hand? Not likely. Give me a
failure mechanism that is likely.

Jim


"Jay Honeck" wrote in message
news:iQRNe.266478$x96.133671@attbi_s72...


In fact, I would never have guessed that this kind of a hair-brained "fuel
management" procedure would merit a serious discussion in these
newsgroups. To even contemplate running a tank dry in the air, let alone
propose it as a standard -- even beneficial (?!) -- procedure, makes for
astonishing reading.

Recently, Ron Rosenfeld posted:

On Thu, 18 Aug 2005 15:42:31 GMT, "Jay Honeck"
wrote:

IMHO, proper fuel management means never even coming *close* to
running a tank dry, let alone doing it intentionally.

And how do you know how much fuel you really have in your tanks?

At most all you've learned is what the fuel capacity of your tanks are,
and that could be more accurately established while on the ground, FWIW.
In fact, the POH should suffice, unless you intend to violate FARs as a
regular practice. Given that "how much fuel you really have in your tanks"
is only one factor in how long you can continue to fly, and that those
other factors aren't addressed by running your tanks dry, what *is* the
point in doing so?

Neil

"Neil Gould" wrote:
At most all you've learned is what the fuel capacity of your tanks are,
and that could be more accurately established while on the ground, FWIW.
In fact, the POH should suffice, unless you intend to violate FARs as a
regular practice.

What FAR says you may not run a tank dry?

Given that "how much fuel you really have in your tanks"
is only one factor in how long you can continue to fly, and that those
other factors aren't addressed by running your tanks dry, what *is* the
point in doing so?

Assume you are flying something with two tanks and no "both" position on
the fuel selector. You're 30 minutes from your destination, which would
you rather have: an estimated 30 minutes of fuel left in each tank, or have
one tank dry and an estimated hour's worth in the other?

I'm not following this thread about running tanks dry. Without an
accurate fuel flow meter (e.g. JPI or EDI) how can you really know
how much fuel is left? Good example - flight from Denver to OSH had
me seeing 132 mph IAS and 155 mph ground speed on the GPS. But I
was also running much higher RPM than usual (almost loaded to the
brim, about 2340/2400 pounds). Great tail wind. But I also used much
more fuel than I planned for due to the higher RPM use.

(remember, my ground is 5500 ft., so I lean by default, which saves
fuel)

In the flat lands, I was unable to lean as much as I usually do,
hence the fuel usage was more than indicated even in the POH and
Lycoming manual for fuel.

Coming home, just the reverse - serious headwinds, high RPM and
more fuel used than I expected. How would knowing a more
accurate fuel capacity help? To me it seems that knowing fuel
usage is more critical than fuel capacity.

Or am I showing my ignorance again? Wouldn't be the first time...

NB: I had planned on installing either JPI or EDI fuel flow meter
this year at the annual but at this point it's a luxury and not
a safety item for me. Since my body doesn't like more than 2 hours
of flying at a time (altho I did 3+ on this past trip) I don't
worry about running out of fuel -- usually.

Blanche wrote:


Coming home, just the reverse - serious headwinds, high RPM and
more fuel used than I expected. How would knowing a more
accurate fuel capacity help? To me it seems that knowing fuel
usage is more critical than fuel capacity.

Without a fuel flow gauge you can't know you're fuel usage unless you
know how much each tank holds. My 182 has 42 gallon bladder tanks. I
recently replaced my left tank with a brand new one. If I wouldn't
have run it dry I would never have known that it actually holds 44 gallons.



NB: I had planned on installing either JPI or EDI fuel flow meter


Avoid JPI like the plague.