Running dry?

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.

The fact that you consider it "hair-brained" does not make it so.

To even contemplate running a tank dry in the air, let alone propose
it as a standard -- even beneficial (?!) -- procedure, makes for
astonishing reading.

Huh. I've run my tanks dry on occasion, for a couple of reasons. First
of all, I wanted to calibrate my new fuel flow gauge. With 56 gallons
in the tanks (28 on each side), I ran one side dry and noted the fuel
used - good within 0.1 gallons out of 28 - I was happy. After I landed,
with 15 gallons left in the other tank (and with a fuel burn on that
trip of about 8.5 gal/hr) I still had almost a 2 hour reserve. It takes
me about 3 seconds to switch tanks, and I do so as soon as I hear the
engine start to stumble. It never stops firing, and it CERTAINLY never
stops rotating - not at 180 Kts TAS at 11.5K ft.

Plus, when I would run one tank dry BEFORE I had the FF gauge, it would
be the only time that I would know EXACTLY how much fuel I had left in
the plane. Seems like something worth knowing.

I'm totally confused as to what the dangerous part of this action might
be. The engine was running before - it'll run after 3 seconds of not
quite getting enough fuel. And since the prop doesn't stop turning (I
have to slow below about 90 Kts before that would happen), it starts
right back up as soon as the fuel returns.

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
http://www.cozybuilders.org/
Copyright (c) 2005

"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

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.

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.

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.

What does it serve to know FUEL FLOW unless you can calulate that again
CAPACITY?

How does it help to know how much money you spend if you don't know how much
you have in the bank? (Insert joke about "How can I be out of money, I still
have checks in my checkbook?")

In article ,
Newps wrote:

Avoid JPI like the plague.

My club has been installing JPI's on most of our planes. It is true that
they're over-priced, and have totally inscrutable user interfaces, but this
is true of almost all avionics. What in particular makes you not like JPI?

Roy Smith wrote:

What in particular makes you not like JPI?

For me, I avoid them because they're absolute *******s. I will not support them
with my money.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

C'mon George, tell us what you REALLY think of them {;-)

Jim



"George Patterson" wrote in message
news:9d4Oe.1416$IG2.824@trndny01...
Roy Smith wrote:

What in particular makes you not like JPI?

For me, I avoid them because they're absolute *******s. I will not support
them with my money.

Roy Smith wrote:
In article ,
Newps wrote:


Avoid JPI like the plague.


My club has been installing JPI's on most of our planes. It is true that
they're over-priced, and have totally inscrutable user interfaces, but this
is true of almost all avionics. What in particular makes you not like JPI?

Their attitude towards their customers. Customers are a necessary evil
to JPI.