FADEC = complex

The feds have just designated a plane with retractable gear, flaps, and
FADEC as a complex.

Bob Gardner

Bob Gardner wrote:
The feds have just designated a plane with retractable gear, flaps, and
FADEC as a complex.

I thought FADEC was simpler. :-)

Matt

Matt Whiting writes:

I thought FADEC was simpler. :-)

Simpler when things are going well, much more complex when things go
wrong. Like all fly-by-wire systems.

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Bob Gardner wrote:
The feds have just designated a plane with retractable gear, flaps, and
FADEC as a complex.

I thought FADEC was simpler. :-)

Matt

I believe that there are presently FADEC systems offered with one-peice
props (such as the Liberty) and with constant speed props controlled by the
FADEC (such as the Cirrus). Presuming that the announcement, which I have
not read, pertained only to FADECS controlling constant speed props; I
believe that it would really only be a clorification rather than a change.

Peter

Mxsmanic wrote:

Matt Whiting writes:


I thought FADEC was simpler. :-)


Simpler when things are going well, much more complex when things go
wrong. Like all fly-by-wire systems.

There is no change in complexity when things go wrong with FADEC.

Newps writes:

There is no change in complexity when things go wrong with FADEC.

Yes, there is, because digital systems have different failure modes
from those of analog systems, and digital failure modes are often
catastrophic failure modes.

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Mxsmanic wrote:
Newps writes:


There is no change in complexity when things go wrong with FADEC.


Yes, there is, because digital systems have different failure modes
from those of analog systems, and digital failure modes are often
catastrophic failure modes.


Spoken like a sim pilot. If you had the slightest idea what the hell
you were talking about you would know that when the FADEC fails, usually
the computer goes belly up but it could be an electrical power loss, the
engine continues to run but does so at a very rich setting. If the
FADEC controls the prop then that goes to high RPM. The pilot doesn't
have to do anything except land and landing immediately isn't necessary
either. These failure modes are a requirement for certification.

Mxsmanic wrote in
:

Newps writes:

There is no change in complexity when things go wrong with FADEC.

Yes, there is, because digital systems have different failure modes
from those of analog systems, and digital failure modes are often
catastrophic failure modes.

You should be advised that not all digital systems are designed like
Windows...

For example, most of today's cars are designed with computer controlled
systems as well. Yet you don't see cars explode every time you click the
right turn signal.

Newps wrote:
Mxsmanic wrote:
Newps writes:
There is no change in complexity when things go wrong with FADEC.

Yes, there is, because digital systems have different failure modes
from those of analog systems, and digital failure modes are often
catastrophic failure modes.


Spoken like a sim pilot. If you had the slightest idea what the hell
you were talking about you would know that when the FADEC fails, usually
the computer goes belly up but it could be an electrical power loss, the
engine continues to run but does so at a very rich setting. If the
FADEC controls the prop then that goes to high RPM. [..]

Seems like you just proved his statement that digital failure modes are
different. If my analog (mechanical in this case) prop control fails,
it doesn't affect my mixture at the same time, as you're saying FADEC
does.

At the same time: Mxsmanic, apparently they've designed FADEC to fail
without being catastrophic.

My own personal worry is coming automobiles with totally electronic
steering and brakes. I'm sorry, even thoughI design reliable embedded
systems and I still would hate owning a car like that :-)

Kev

Newps writes:

Spoken like a sim pilot.

No, spoken like a computer specialist.

If you had the slightest idea what the hell
you were talking about you would know that when the FADEC fails, usually
the computer goes belly up but it could be an electrical power loss, the
engine continues to run but does so at a very rich setting.

FADECs can fail in all sorts of ways, depending on the software bugs
they contain.

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