Running dry?

Doing it not only checks the guage indication.
It also checks.

1. Fuel Pickup integrety
2. Fuel Cell Integreity (Bladders especially)
3. Fuel Filling issues (some airplane are difficult to fill completely)

Brian

On Thu, 18 Aug 2005 09:58:18 -0400, "Peter R."
As far as disadvantages, I am concerned about what might happen with the
sediment in these aging fuel bladders as the fuel empties. But, I have
read articles that dispel this myth so perhaps this is a non-issue.

Maybe this one? http://www.avweb.com/news/columns/182044-1.html

"The Creeping Crud OWT
Then there is the secondary OWT that says something like "But what if some
crud gets sucked into the system from the tank bottom?" Give me a break!
Think about this, for a moment. There are three areas where "crud" might be
a concern. Crud lying on the bottom, crud suspended in the fuel, and crud
floating on the surface. When we fuel the airplane, fuel is injected rather
violently, stirring up the whole tank. When we fly in turbulence, fuel
sloshes rather violently around the tank. Do you really think anything will
be peacefully lying on the bottom, year after year? If it were, why would
running the tank dry stir it up, and if it's that tenacious, how on earth is
running the tank dry going to magically pick it up?

How about suspended crud? It is no more, or less likely to be sucked into
the fuel lines at any fuel level. Floating crud, on the surface? Well,
maybe, but can you name me something that will do that? And if there is,
well, how much of it will you allow, before you rip the tank out for
"cleaning," or how WILL you get it out, someday? Just how, and when, will
you identify it, detect it, and get rid of it? And, how much fuel do you
want as a "buffer" below the floating crud, to keep from sucking it in? In
fact, if there is a little something floating on the surface, I WANT it to
be sucked into the fuel lines, preferably a little at a time, so that the
strainers and filters can catch it, and alert me that something is going on
in there. The likelihood of there being enough to cause a problem is remote,
at best, and if running a tank dry will pick up a little crud, then running
a tank dry often is a very good thing, because you'll catch it a little at a
time, and drain it out the strainer.

Of course, if you keep the tank full most of the time, and the cap on, and
drain the sumps often, there isn't any way for crud to get into, or stay in
the tank in the first place."

Nope. I have drained the tanks before and used that measurement to
calibrate the computer. Draining the tank shows the computer to be
correct within 0.1 gallons (1/10 of a gallon). Running the tank dry
once doesn't tell me if I get a new leak but I do also have accurate
fuel gauges. If you fly long trips as often as I do, spend some money
on the gauges and a good, calibrated fuel computer rather than scar the
crap out of your pax.

Too many of you have been reading "The Cheap *******'s Pilot's Guide".
I have good working gauges and a fuel computer that has been
professionally calibrated and verified at each 100 hour inspection. I
don't need to make the wife want to leave me in order to know how much
fuel I have. Flying over the Sierras, dodging TS's is exciting enough,
I don't need to turn off the fan to add more excitment to my life.

Are your gauges accurate enough to reliably tell the difference between
30 minutes fuel at 60% power and empty in tyubulent air?
Will your fuel computer account for fuel that leaves via a cap that has
developed a leak?

Michael

"Robert M. Gary" writes:

Flying over the Sierras, dodging TS's is exciting enough,

Yeah, been there, didn't enjoy it.

I don't need to turn off the fan to add more excitment to my life.

We seem to have diverging groups. Some of us see running a tank (nearly)
dry as a non-event. Others see it as "turn[ing] off the fan". I've seen
a few references to the *possibility* that some planes will actually lose
power for more than an instant if the tank is run down. Are any of us
who run the tanks "dry" actually experiencing this? I suspect that the
reason most of us who do this don't get so excited about it is because it
is such a non-event. Is that plane-specific?

(I've had it take a long time to figure out which tank just went dry when
an engine started surging. It wakes me up but it's sure not so exciting
that I'd avoid the practice.)

--kyler

In article .com,
"Michael" wrote:

Are your gauges accurate enough to reliably tell the difference between
30 minutes fuel at 60% power and empty in tyubulent air?
Will your fuel computer account for fuel that leaves via a cap that has
developed a leak?

Michael

INHO, the biggest error thet the "don't run it dry" crowd fails to grasp
is that, at the end of the flight, it is far better to have that 45
minutes of fuel in a single tank, rather than scattered among three or
four tanks totaling 45 minutes worth.

That is where a lot of fuel starvation accidents happen. Pilot gets busy
on approach, thinking he has selected a tank with enough fuel in it when
that fuel is in another tank.

On Fri, 19 Aug 2005 09:17:22 +0200, Thomas Borchert
wrote:

Robert,

I know exactely how
much fuel is in each tank.


Nope, you don't. In fact, without running the tanks dry at least once
(or emptying them in the hangar), you have no idea. You know how much
has gone from the tanks if there is no leak. That doesn't tell you at
all how much is left.

Coming back from HTL with full tanks, the gauge on the left main
started down. I didn't know if I had a gauge problem, or the tank was
leaking, or if the quick drain had failed. It was moving fast enough
that if it was correct I was going to be really wing heavy on the
right. As soon as I noticed the gauge going down I switched to the
right tank.

At any rate, I had filled the tank prior to starting out, but I had no
real idea as to how much gas was left. I knew I'd only burn about 4.5
gallons on the way home so I knew what *should* be in there, but not
how much I really had.

I did a precautionary landing at GDW. A check showed no leak and the
level was where it should be. When I fired back up the gauge was
reading properly.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

The primary function of the fuel gauges in most light aircraft is to
indicate when the master switch is on.

Jim



I did a precautionary landing at GDW. A check showed no leak and the
level was where it should be. When I fired back up the gauge was
reading properly.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On 19 Aug 2005 10:48:45 -0700, "Robert M. Gary"
wrote:

Too many of you have been reading "The Cheap *******'s Pilot's Guide".
I have good working gauges and a fuel computer that has been
professionally calibrated and verified at each 100 hour inspection. I
don't need to make the wife want to leave me in order to know how much
fuel I have. Flying over the Sierras, dodging TS's is exciting enough,
I don't need to turn off the fan to add more excitment to my life.

What happens if a tank develops a leak? We had a Comanche go down a
few years ago due to running out of fuel. He took off with full fuel
and at that point should have had near half left.

The verdict? Mice had chewed holes in the bladders. When he fueled
up the pressure kept the bladders sealed against the metal so no leaks
were apparent, but once in the air the turbulence kept him bouncing
enough that the tanks lost a lot of fuel.

He knew how much he burned, but the gauges were bouncing too, or at
least until they were near empty. He was doing really well on that
paved mountain road until he found that mail box sent on a steel pipe
full of concrete.

No injuries except for the airplane and with a new wing it's been back
flying for some time.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com