NW_Pilot's Trans-Atlantic Flight -- All the scary details...

On Mon, 02 Oct 2006 18:59:11 GMT, Jose
wrote in :

How would the fuel get to the main tanks in the first place?

Read Mr. Rhine's narrative. The FI system has a fuel return line to
return unused fuel pumped to the engine back to the wing tank(s).

The FI system has a fuel return line to
return unused fuel pumped to the engine back to the wing tank(s).

Is this dumb, or is there a good reason not to return fuel to the tank
whence it came, in this case, the ferry tank?

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

"Larry Dighera" wrote in message
...
Here's an example of what I consider a classic flame:

You know - they say that people with
I.Q.'s over 40-points apart are pretty
much unintelligible to each other.
That's just a random observation with no
ulterior meaning attached to it :P
As I read it, stupidity installed itself long
before you clocked three score and ten,
you are merely coming out, in bloom.
Let's pretend that you really are not an
obnoxious ignorant, cowardly, motor-mouthed
cretin exuding digital diarrhea as a pretext
to seeking a Life? About as topical as the
man who thinks its cool to jam garden gnomes
headlong up his ass to prove a qualified
opinion on de rigueur art decor, your puerile
attempt at self adulation is hilarious!
Unfortunately my having no respect for you
means your opinion of what I or anyone else
needs to respect means absolutely nothing.

Don't forget to **** yourself on your way
out, moron.


Larry,

Who'd you **** off over in alt.languages.english?

A few years ago, I remember reading an excellent book on general design of
modern avionics. In particular, one thing that I believe is different between
Garmin's baby and what they have in B-s and A-s is redundancy. The whole thing
there is doubled, and some critical components are tripled. And then there's
a whole body of software that takes care of voting-elimination among inputs.
By design, the event of the computer reboot (i.e. all three redundant computers
reboot) is perhaps as likely as the event of all four engines quitting at the
same time. What surprises me is that Garmin got FAA approval for such a system,
whereas it doesn't even come close to what "normal" glass cockpit is supposed
to be like in terms of robustness of system design. I understand it's all done
in the name of affordability, but this is clearly a dangerous game to play.

If you think about it, just to be able to claim any kind of "robustness",
you should be reasonably sure that there's no single failure that will take
the whole system out, right? And there we go: excessive fuel venting took
airspeed indicator out completely, and CO indication out completely. And this
is aside from any software bugs; this is the way G1000 is supposed to work
by design!

So, I guess my point is: you can't just take a steam-gauge-type airplane,
replace all the individual *independent* instrument systems with one
electronic box, and claim you've got an equally reliable plane. No way. By
tying everything together and establishing inter-system dependencies that
never existed before, you increase your likelihood of a catastrophic failure
by orders of magnitude. If you want to use an all-in-one instrument system,
you need to redesign the airplane and fit it with redundant systems to
compensate for that loss of overall reliability.

That's the book, btw:
http://www.amazon.com/Avionics-Handb...e=UTF8&s=books


Andrey


Larry Dighera wrote:
On Mon, 02 Oct 2006 10:18:13 GMT, Matt Whiting
wrote in :

... , it isn't a good idea to have all of your
eggs in one basket, especially when that basket is made of software! :-)

It would seem that Airbus has successfully grappled with this issue.
Perhaps Cessna and Garmin should get a clue from them.

"Jose" wrote in message
m...
The aux tank was connected directly to the engine after the aircraft fuel
system, Not to the wing and the provided documentation and system
description mentioned nothing about the fuel return to the main tanks.

How would the fuel get to the main tanks in the first place? Is the
engine the only connection? (if so, with the fuel selector OFF that
should block fuel flow to the main tanks). Is there a vent line that
connects them?

Excess fuel from the engine is returned to the main tanks. Twin Cessna's
are the same way; if you switch to the aux tanks before burning a certain
amount out of the mains (90 minutes for the large aux tanks) the mains will
overfill and vent overboard before the aux tanks are empty.

Allen

("Larry Dighera" wrote USEFUL INFORMATION)
If the lurkers post USEFUL INFORMATION, that is correct and supported by
independent citations, they have nothing to fear. Otherwise, it would
appear that the 'flameage' is working.


"Bloviating idiot" is still my favorite ...flameage.


Montblack

"Jose" wrote in message
m...
The FI system has a fuel return line to
return unused fuel pumped to the engine back to the wing tank(s).

Is this dumb, or is there a good reason not to return fuel to the tank
whence it came, in this case, the ferry tank?

Jose

There would probably be a significant amount of under the cowling work that
would have to be done. So the good reason is cost.

("Longworth" wrote)
Adventure like this was made for adrenaline junkie like you ;-)
Congratulations for an exceedingly well done job. Actions speak louder
than words, it takes both a cool head and good piloting skill to handle
this scary event. I don't think that you can ever silent net armchair
critics, Monday morning quarterbacks etc but I hope that you have erased
some doubts in the mind of some of your 'frequent' critics.


Agreed.

Congratulations! Well done.


Montblack

"Larry Dighera" wrote in message
...
On Mon, 2 Oct 2006 11:47:43 -0700, "NW_Pilot"
wrote in
:

When on the phone with Cessna engineering and
Garmin support they said they had a similar problem
during stalls and slow flight.

So, the uncommanded FIS rebooting was a known issue, and both
manufactures chose to release their products for use? One would have
thought Cessna would have learned not to do that from their seat-rail
issue. I hope the premiums are paid current on their errors and
omissions insurance policies.

Yea, its a scary thought! The G1,000 System is nice when it works "Great IFR
platform for situational awareness" But they do need some manual back up of
some critical items for safe IFR flight. I know I would not fly into IFR
conditions in a G1000 equipped airplane with my family or a passenger on
board. After sitting for 70 hours on Cessna version of the G1000 Scares the
hell out of me and it takes a lot to scare me! To many bugs and failure in
70 hours of flight! Look at my finial day the Tach. even failed!

"Allen" wrote in message
. ..

"Jose" wrote in message
m...
The aux tank was connected directly to the engine after the aircraft
fuel system, Not to the wing and the provided documentation and system
description mentioned nothing about the fuel return to the main tanks.

How would the fuel get to the main tanks in the first place? Is the
engine the only connection? (if so, with the fuel selector OFF that
should block fuel flow to the main tanks). Is there a vent line that
connects them?

Excess fuel from the engine is returned to the main tanks. Twin Cessna's
are the same way; if you switch to the aux tanks before burning a certain
amount out of the mains (90 minutes for the large aux tanks) the mains
will overfill and vent overboard before the aux tanks are empty.

Allen


And there is a note in the description of that fuel system that explains
that! Which was not included in the description of the modified fuel system
on the 172.