FADEC = complex

Greg Farris writes:

That is demonstrably false!
There are several documented cases of mechanical failures of throttle
linkages in airplanes, and when it happens it is a genuine,
life-threatening emergency.

As I've said, failure modes are very limited for mechanical throttles,
and generally they are not catastrophic. A failure of a linkage, for
example, may deprive you of throttle control, but it is much less
likely to peg the throttle at idle or full power (although this
depends on design).

--
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In article ,
says...


Greg Farris writes:

That is demonstrably false!
There are several documented cases of mechanical failures of throttle
linkages in airplanes, and when it happens it is a genuine,
life-threatening emergency.

As I've said, failure modes are very limited for mechanical throttles,
and generally they are not catastrophic. A failure of a linkage, for
example, may deprive you of throttle control, but it is much less
likely to peg the throttle at idle or full power (although this
depends on design).

--



As I've said - as I've said - as I've said. . .
You are simply, demonstrably, completely WRONG!
It's easy to prove. Databases exist on these accidents, and they prove you
completely wrong.

"As I've said", is a meaningless phrase for someone who lives in complete
ignorance of the subject.

The USUAL failure mode for mechanical linkages results in complete, or
nearly complete power loss. There are dozens or accidents in the database
for this failure mode - several of them fatal.

I am not aware of accidents cause by software failure of Fadecs - perhaps
there have been - but these are certainly rare compared with mechanical
failures of linkages.

The databases contain thousands of accidents directly attributable to
mechanical failures in airplanes. I am not aware of ANY accident in which
software failure of a system was causal. There are plently of situations
where crew have misinterpreted situations, but I cannot think of any
accident in which a software failure has created an "unrecoverable"
situation, as has been the case in hundreds of mechanical failure
accidents.

Greg Farris wrote:
I am not aware of accidents cause by software failure of Fadecs - perhaps
there have been - but these are certainly rare compared with mechanical
failures of linkages.

Bell Helicopter(s):

http://www.ntsb.gov/Recs/letters/2004/A04_68_69.pdf

Osprey:

http://www.defenselink.mil/news/Apr2...200104093.html

Chinook Helicopters:

Unknown if its FADEC caused actual accidents, but is a suspect.
Uncommanded engine excursions, and false failure indications in early
software revisions.

Airbus:

The most famous of all, the Airbus "low pass" at the French air show,
when the FADEC throttles refused to power up (thinking the plane was
landing) and the plane settled into the trees. Not a bug per se, but
certainly poor software planning and it resulted in changes in fly by
wire thinking.

So in general, yes the failures resulting in deaths seem to be rare.
Failures that result in pilots needing a new set of underwear are a
little less rare. IFSD (In Flight Shut Downs) happen. In one case,
the ECC software kept flopping between power supplies and shut down the
engine. The software was fixed.

There are not enough small plane FADECs out there yet to judge for GA.
Hopefully the software is better tested than, for example, the G1000
that almost messed up NW_Pilot's recent Atlantic crossing!

Kev

Kev,

The most famous of all, the Airbus "low pass" at the French air show,
when the FADEC throttles refused to power up (thinking the plane was
landing)


Oh? Please quote the passage from the accident report that says this.
I'd be really interested. All I know is the passage where it losely
says: The pilot actively and consciously set up the system to
circumvent all the safeguards built into it to make the plane do the
stupid unapproved show-off-maneuver (sp?) instead of preventing an
accident like this as it was designed to. And after doing that, WTF did
he expect?

--
Thomas Borchert (EDDH)

In article om,
says...


The most famous of all, the Airbus "low pass" at the French air show,
when the FADEC throttles refused to power up (thinking the plane was
landing) and the plane settled into the trees.


It is anything but demonstrated that the aircraft systems did anything
unexpected in this accident. The pilot tried to make this claim at the
outset, but ended up being saddled with responsibility for his show-off
manoeuver. The official result of the investigation is that it was the
pilot's fault, and the aircraft has been exonerated of any failure.



Not a bug per se, but
certainly poor software planning and it resulted in changes in fly by
wire thinking.

Much more to change thinking on matters of pilot training. the claim of "poor
software planning" is unsubstantiated.




So in general, yes the failures resulting in deaths seem to be rare.

Yeah, really.

Greg Farris writes:

It is anything but demonstrated that the aircraft systems did anything
unexpected in this accident. The pilot tried to make this claim at the
outset, but ended up being saddled with responsibility for his show-off
manoeuver. The official result of the investigation is that it was the
pilot's fault, and the aircraft has been exonerated of any failure.

I'd be wary of any "official" evaluation of this accident, given that
the flight recorders were tampered with.

Much more to change thinking on matters of pilot training. the claim of "poor
software planning" is unsubstantiated.

It was a combination of both. Airbus had already issued engineering
bulletins on anomalous FADEC behavior in the aircraft.

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Greg Farris wrote:
In article om,
says...
The most famous of all, the Airbus "low pass" at the French air show,
when the FADEC throttles refused to power up (thinking the plane was
landing) and the plane settled into the trees.

It is anything but demonstrated that the aircraft systems did anything
unexpected in this accident. The pilot tried to make this claim at the
outset, but ended up being saddled with responsibility for his show-off
manoeuver. The official result of the investigation is that it was the
pilot's fault, and the aircraft has been exonerated of any failure.

LOL. If you believe official investigations all the time, then I've
got a bridge for you. Of course the pilot was blamed. But they
changed the software afterwards, and Airbus officials had this to say:
"Until the crash, there was a genuine psychology around Airbus that it
had designed a crash-proof airplane because of the hard protections.
The repercussions from that accident continue to reverberate,"

Not a bug per se, but certainly poor software planning and it resulted in
changes in fly by wire thinking.

Much more to change thinking on matters of pilot training. the claim of "poor
software planning" is unsubstantiated.

Hardly wry grin. The pilot did what he was told to do, but had two
hits against him. First, he was told to fly by at 100'. He did so,
not knowing that Airbus had a bug in the Atlimeter software, and he was
really at 30'. This screwed him, since he also didn't know that
Airbus had issued an bulletin the month before the crash, stating that
the engines sometimes didn't respond to throttles at low altitudes.
The pilots had not gotten the notice yet. The engine software was
modified after the crash.

Kev

Kev,

If you believe official investigations all the time,


Oh yeah, conspiracy theories are so much better.

--
Thomas Borchert (EDDH)

Thomas Borchert wrote:
Oh yeah, conspiracy theories are so much better.

Are you always such a snotty child?

I worked in Intelligence and for NSA. I have always said, "Never look
for a conspiracy when it can be explained by sheer stupidity or
bureacracy."

But in this case, it's obvious that France was not about to let Airbus
get blamed. Not much different from blaming the co-pilot for ripping
off that Airbus rudder.

Kev