Running dry?

Neil Gould wrote:

The FARs address minimum fuel levels when you arrive at your destination.
If you have less than the required amount when you land, you are in
violation.

Not true. The FARs state that you have to *plan* the flight so that, if all goes
as planned, you have a certain amount of fuel in reserve. Nothing says you
actually have to have that amount when you land.

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.

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.

On Sat, 20 Aug 2005 04:00:49 GMT, "Jay Honeck"
wrote:

That is possibly the dumbest thing I've ever read in these newsgroups.

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

And now you expect us to call you names, too?

Readthe other posts here, and you may learn that it is not as simple to
judge
as you make it.

I'm sorry, was I calling someone a name? I thought he was quoting an
article?

I have read all the posts in this thread with great interest. Nothing said
here has come close to explaining how the minimal utility you might get from
running a tank dry could possibly overcome the very real danger that the
engine might stop.

The engine isn't going to stop. It will most likely quit developing
power, but other than being quieter, the prop keeps right on spinning.
Turn the fuel selector to a tank that still has gas in it and the
engine will go right back to developing power. If you are quick it
only sounds like a hick up.


My statement stands -- it's a dumb idea.

I might think differently with a carbureted engine, but this pretty
much goes back to the debate of instructors pulling the mixture or
throttle on power outs, except this is of a far shorter duration. I've
had tanks un port on a "missed" while climbing out. Now that will get
your attention. The old Deb doesn't have any baffles in the tanks so
any approach want's to be on the fullest main. On cross countries if
you don't burn the one side down you are going to be carrying a lot of
gas and losing about an hours flying time.

I've had one complete engine failure, but it wasn't due to running a
tank dry. That too, gets your attention right away.

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

How about a corroded, iced or otherwise inoperable selector valve?

Valves do fail. I can conceive of a situation in which the selector handle
might simply break off.

And what's the likelihood of carb ice when power tails off due to fuel
starvation? That might interfere with the restart.




"RST Engineering" wrote in message
...
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.

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.

Jay,

Sorry, even Einstein had dumb ideas. This is one of Deakins...


Well, while you're certainly entitled to your opinion, it might be
prudent to not offer it in such absolute terms in this case. It might
be wise to say something like "I wouldn't do it, but if it works for
you guys, so be it." Instead, you try to offer pseudo-facts about
alleged accidents caused by this. To which, with all due respect, I
say: THAT is dumb BS.

--
Thomas Borchert (EDDH)

"Seth Masia" wrote in message
...

How about a corroded,

You can't correct for lousy maintenance.


iced or otherwise inoperable selector valve?

Everybody (in the lower 48) who has had an iced valve, raise your hands?
None? I thought so.

Inoperable? And you departed the airport this way? Hm.


Valves do fail. I can conceive of a situation in which the selector
handle might simply break off.

In which case you've got just about as many options as if you burn it down
to a couple of gallons before you do the old switcheroo. Which is why I
posted that this is an improper technique over rocks, trees, and water.



And what's the likelihood of carb ice when power tails off due to fuel
starvation? That might interfere with the restart.

With a one to two second "off" time before restart? Not bloody likely. The
exhaust stacks remain hot enough that carb heat is still effective.

Am I advocating for or against running one dry? Not really. There have
been times I have intentionally run one dry. THere are times I wouldn't run
one dry for all the tea in China. All I want is a LIKELY scenario for a
failed restart with a semifull tank selected.

Jim

"Seth Masia" wrote:

How about a corroded, iced or otherwise inoperable selector valve?

If you think valve (or selector handle) failure is a significant risk, then
wouldn't it make sense to change tanks as infrequently as possible?

And what's the likelihood of carb ice when power tails off due to fuel
starvation? That might interfere with the restart.

Carb ice isn't going to form in a few seconds.

Recently, Roy Smith posted:

"Neil Gould" wrote:
What FAR says you may not run a tank dry?

The FARs address minimum fuel levels when you arrive at your
destination.

I'm not aware of any such regulation. I suspect you're thinking of:

91.151 Fuel requirements for flight in VFR conditions.

[...]
But that only talks about how much fuel you have at takeoff, not at
landing.

You're (all) right; I was thinking of that FAR, and I stretched the point
too FAR. ;-)

I regularly fly something with two tanks and no "both" position
(PA28), and my preference is to arrive at my destination with more
than 30 minutes worth of fuel, period. I see no point in pushing
those limits any more than seeing how much over gross I can fly.
IMO, such points are just useless information. YMMV.

I also think landing with 30 minutes of fuel is too little. So, how
much is enough? Let's assume we can agree on an hour, which in a 180
HP PA-28 means about 8 gallons. You take off with 48 usable and fly
for 5 hours, leaving an estimated 8 gallons left. Which is a more
useful configuration to have at this point, an estimated 4 gallons
usable remaining in each tank, or an estimated 8 gallons usable in
one tank and the other one dry?

I would feel more comfortable with 4 in each tank than with a dry tank.

I had an interesting thing happen to me in an Archer. During an XC, a
facia screw on the fuel selector had worked loose and backed out enough
that when I went to switch tanks, it wouldn't go into that position. My
choices were the tank I was on, or off. I'm glad the tank I was on wasn't
dry, because when the A&P looked it over, it took him around 15 minutes to
figure out what was wrong. Needless to say, I wouldn't have figured that
out en route before hitting the ground, because I couldn't see the problem
from my seated position. Stuff happens.

Neil

"Neil Gould" wrote:

I also think landing with 30 minutes of fuel is too little. So, how
much is enough? Let's assume we can agree on an hour, which in a 180
HP PA-28 means about 8 gallons. You take off with 48 usable and fly
for 5 hours, leaving an estimated 8 gallons left. Which is a more
useful configuration to have at this point, an estimated 4 gallons
usable remaining in each tank, or an estimated 8 gallons usable in
one tank and the other one dry?

I would feel more comfortable with 4 in each tank than with a dry tank.

Let's examine that. We're comparing the relative risk of two events.

Event 1 is that the fuel selector valve fails when you go to switch to the
tank containing the remaining 8 gallons.

Event 2 is that your estimate of how much fuel is left in the tank is wrong
by 4 gallons (16%).

Which is more likely?