On Jan 14, 4:52 pm, Bertie the Bunyip wrote:
akiley wrote :



On Jan 14, 3:33 pm, Bertie the Bunyip wrote:
akiley wrote in news:2e7dbffb-645c-49b6-9687-
:

Hi All, I'm working on my multi rating in a Beech Duchess. I'm
curious about an item that doesn't seem well covered in the POH and
elsewhere for that matter.

What if you loose one engine at altitude, allowing plenty of time
to try to fix. You determine that you ran the right tank dry of
fuel. According to the fuel diagram, you should be able to run both
engines off one tank. The fuel line exits each tank and splits:
one going to the opposite fuel selector and one going to the
closest engines fuel selector.

If this is doable, why is it not talked about more? It's not a
"fix" option on the checklist and not discussed in the text of the
POH. Crossfeed is considered an emergency operation according to
the POH, and also "level flight only". Could this be why?
Possible fuel starvation on the crossfeeding engine from
maneuvering to land, where it may be safer to feather and secure
the dead engine and do your one shot landing.

... akiley

I have no idea what you're asking here. If you've lost an engine, why
would you be needing to run both off one tank?

Now, if you mean that you still have a long way to go and that you'll
run one dry before you get where you are going, then , yes, that's
what it's for.
You also want to alternate a bit to keep any imbalance from getting
crazy. I haven't flown a duchss n a long time, but I don't remember
there being anything too strange about the crossfeed arrangements.
But if you lost one there's nothing stopping you from crossfeeding
from the oppostie tank. Likelywise, if you have a leak in one tank,
there's no reason I can see you can't run both engines off of the
remaining tank. Sounds like they are (quite rightfully) discouraging
2recreational crossfeeding" that some guys do just to "balance em out
perfectly" This usually leads to a massive imbalance, or even worse,
having both engines flame out due to ou getting distracted and
forgetting.

It happens.

Bertie

In essence, I was asking if there was any reason not to run both
engines off one tank. In singles, "switch tanks" always seems to be
part of the emergency checklist for a rough engine, yet in the
Duchess POH (and a Seneca I for that matter) "crossfeed" isn't
mentioned as a diagnostic step where it seems like is should be. I
was wondering if I had missed something.

OK, if I'm following you, you're suggesting that you've lost an engine
for no apparent reason. You decide that it might be a fuel problem, so
you want to feed off the tank on the opposite side to see if that fixes
it.
Sounds like a good idea to me. You would have to be very, very careful
that it wasn't a fuel line on the failed side that caused the problem in
the first place, otherwise you could lose all the fuel. That's what
happened to that A330 that deadsticked into the Azores. But it sounds
like a reasonable thng to do if that is what you suspect the problem is.
Just make sure you do it slowly and deliberately. you don't want to end
up gliding due to a poor selection.
You might also consider, on the day, the wisdom of relighting an engine
with a fuel problem. It's all a trade off of various risks. Wx, how far
you have to go vs how much gas you got left, that sort of stuff. If you
don't really need it to get where you are going, it might be better not
to take the risk. If you are in the middle of a mountain range and you
need it to keep your altitude above MORA at night, different story. Not
that you should be there anyway.
Manufacturers, the FAA and schools will steer you towards the checklists
and procedures for some very good reasons. Experience with some of these
situations has produced a pattern of th emost likely causes and the
results of getting too creative with the systems. If they recommend you
do something a certain way, do it that way. But, if you 're off the
page, knowing how the system works will enable you to analyse the
problem with a good chance of a solution.

Bertie

Thanks for the good point. Remember in the original post I made a
scenario where I exhausted the fuel in the right tank. Fuel pressure
and quantity gauges confirmed this. So I decide to try to crossfeed
from the good engine side to the engine that I lost due to fuel
starvation. But good point. What if I lost all the fuel in that tank
because of some problems like a leak that may effect the full tank if
I crossfeed.

.... akiley