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

I find it difficult to believe that the pressure in the wing tank(s)
was significant,

Ok, "overpressure" is the wrong word, but it pumped gas into an overfull
tank causing the fuel to go overboard and read "more than full".

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).
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On Thu, 05 Oct 2006 18:01:50 GMT, Jose
wrote in :


I find it difficult to believe that the pressure in the wing tank(s)
was significant,

Ok, "overpressure" is the wrong word,

That is how the pilot described it, so I'm not so sure of exactly what
the situation actually was.

but it pumped gas into an overfull
tank causing the fuel to go overboard and read "more than full".

While the wing tank did lose fuel through its drain system, I believe
it stopped "reading" all together. Where did Mr. Rhine indicate in
his narrative, that it was "reading" more than full?


After switching to the aircraft fuel (from the ferry tank) strange
things started happening. The 100-gallon ferry tank went dry
after only 7 hours, burning 8 to 9 gallons per hour! Something
just did not add up...
[...]


Then, the G1000 started to go nuts, with the fuel indicators
displaying red X's. Next, I received a CO2 detector failure, then
GPS-1 failure!
[...]


When the G1000 got done rebooting, I found myself missing my
airspeed indicator and fuel gauges -- and it was now displaying a
bunch of other errors. Assessing my situation, I figured that I
had no fuel gauges, the G1000 is continually rebooting, possible
CO2 in the cabin, AND an apparent fuel leak!
[...]


As I grind closer and closer to Narsarsuaq, at about 60 miles out
they send up a rescue chopper, locate me, and guide me in, since
I am unable to make the NDB approach with the G1000 rebooting
itself. (The ADF display is tied to the G1000's HSI.)
[...]


[Day 3]
We finally figured out that the instructions for the ferry tank
were not correct, and really need to be changed before the company
installing the tank kills someone.


The problem was the ferry tank's fuel return line was over
pressurizing the aircraft tanks, causing fuel to vent overboard.
To prevent this, what needed to be done was to FIRST run the
aircraft's left tank down till it was almost empty, THEN turn on
the ferry tank.


The instructions with the ferry tank said only to "Climb to
altitude, then switch to the ferry tank and turn off the aircraft
fuel", then run it till the fuel level hits a mark on the ferry
tank's fuel level indicator. These instructions turned out to be
totally incorrect!


Even Cessna engineering was surprised that the FAA had approved
the instructions for the ferry tank setup, because it also caused
the G1000 to go nuts. Apparently the added pressure in the fuel
tanks pushed the floats in the fuel tank up, which got the Garmin
confused, causing an error that made it reboot. The loss of the
airspeed indicator was caused by fuel vapors entering the pitot
tube -- which also caused the CO2 detector failure!
[...]


[Day 11]
Then the tach started being erratic, saying that my RPMs were 4000
-- yeah, right! Then it went Red X. OK, Garmin & Cessna, you
need to have better quality control. After everything else that
has happened, this makes me not want to every own a newer model
Cessna, or anything with a G1000.

It's difficult to understand how fuel got into the pitot system, given
the placement of the fuel vent and the pitot mast. If the new
Skyhawks don't have fuel balders any longer, perhaps the pitot
plumbing was routed through the wing tank, and the increased pressure
was adequate to cause fuel to seep past the plumbing fittings.

but it pumped gas into an overfull
tank causing the fuel to go overboard and read "more than full".
While the wing tank did lose fuel through its drain system, I believe
it stopped "reading" all together. Where did Mr. Rhine indicate in
his narrative, that it was "reading" more than full?

He didn't - that was speculation as to the cause later on. With the
fuel "more than full", the sensors would be reading "more than full" and
sending that info to the Garmin.

The Garmin went nuts.

OF course, cause and effect has not been determined, but it's a
reasonable starting point for Usenet quarterbacking.

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.

Recently, Jose posted:

but it pumped gas into an overfull
tank causing the fuel to go overboard and read "more than full".
While the wing tank did lose fuel through its drain system, I believe
it stopped "reading" all together. Where did Mr. Rhine indicate in
his narrative, that it was "reading" more than full?

He didn't - that was speculation as to the cause later on. With the
fuel "more than full", the sensors would be reading "more than full"
and sending that info to the Garmin.

The Garmin went nuts.

OF course, cause and effect has not been determined, but it's a
reasonable starting point for Usenet quarterbacking.

What I find interesting in all this Usenet quartebacking is ignoring the
shoddy installation job of other panel-mounted devices:

NW_Pilot
"The chances of myself refering or using this company for tanking is slim
I
did not pick this company the customer did and the customer was not happy
with their services anyway they did a **** poor job at cutting the panel
when they installed the ADF and PS eng. entertainment system. (I could
have
done a better job with a hack saw and a drill) and the painting on the
Horton kit they installed looked like orange peal!"

I think its reasonable to think that some of the G1000's wiring or the
unit itself was damaged during this hack. Even attaching the power to the
ADF or entertainment system in a way that caused the power to the G1000 to
be flaky or intermittent could account for the drastic failure modes he
experienced.

Neil

I think its reasonable to think that some of the G1000's wiring or the
unit itself was damaged during this hack. Even attaching the power to the
ADF or entertainment system in a way that caused the power to the G1000 to
be flaky or intermittent could account for the drastic failure modes he
experienced.

Good point.

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.

Neil Gould writes:

I think its reasonable to think that some of the G1000's wiring or the
unit itself was damaged during this hack.

That would not generally cause software reboots.

It's much more realistic to think that there are fundamental defects
in the G1000.

Even attaching the power to the
ADF or entertainment system in a way that caused the power to the G1000 to
be flaky or intermittent could account for the drastic failure modes he
experienced.

There should be no drastic failure modes at all, under any conditions.

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On 2006-10-06, Mxsmanic wrote:
Neil Gould writes:

I think its reasonable to think that some of the G1000's wiring or the
unit itself was damaged during this hack.

That would not generally cause software reboots.

Unless, of course, it was the power wiring. I suspect a momentary power
interruption could reboot a G1000. There's not much you can do about
that either (short of stuffing a 20 farad supercapacitor in the back of
the device or a fully fledged UPS).

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Dylan Smith writes:

Unless, of course, it was the power wiring. I suspect a momentary power
interruption could reboot a G1000.

It would not do so in synchronization with the software.

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