SAS
I never said the argument was won on Pprune (and neither did I say who the winner was) however it has been won on the street (well in the sky I suppose)
F1100 / twisted
You should not find the suggestion of both engines going offline simultaneously that impossible. Both engines are controlled by the same design of FADEC with the same hardware and the same software inside. Something affecting one engine that is software related (a bug) or from an external source (RF interference, icing etc) is going to have just the same effect on the other engine. If the probability of having a single engine failure is 1 in 10,000 hrs then the probability of a double engine failure is most definitely not 1 in 100,000,000 hrs - its much more probable than that.
On the EC225 fleet we have had 2 cases of double complete AHRS failure, we have had no cases of single complete AHRS failure. The 2 cases were caused by a software bug that didn't agree with the Montrose A platform. Fortunately the third AHRS system uses different hardware and software and remained OK. Had we had 3 AHRS systems of the same design, it might have been an accident (btw the bug was fixed a year or so ago). This is why fly-by-wire fixed-wings have different flight control computers manufacturerd by different companies using different hardware and software (though trying to achieve the same behaviour), rather than just installing 3 of the same kind of control system.
Also bear in mind the 777 that crash-landed at Heathrow the other year - both engines failed to produce power within a few seconds of each other, in that case I think it was fuel icing. The equipment (engines, AFCS computers etc) may seem to be separate, but there are always common elements.
HC