FADEC = complex

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