Was really curious as to what Airbus was using, thanks for this! Why not just use the latest CPUs though? I can't imagine the cost would be relatively significant in the greater scheme of things. Are the legacy CPU's really better for this use-case?
Planes don't need insane multitasking processing power like our smartphones or PCs. They mostly do signal processing and sensor fusion in a tight loop which is quite trivial even for legacy CPUs as it's basic flight math equations which results in highly optimized code.
In terms of aero chips, basic is always better as you want a silicon that's tried and tested for decades to have a deep understanding of it's quirks and bugs so you know the code execution is reliable.
Manpower could also be a bottleneck. Design talent is not what it used to be in the first world after much of production moved overseas.
Yes. Legacy CPU's have the advantage of years and years of testing. Newer CPU's are not as reliable for safety-critical systems inasmuch as not all the kinks have been worked out, and there may be catastrophic bugs in newer designs that won't be discovered until mass deployment on consumer markets.
Meltdown and Spectre have sent shock-waves through the safety-computing industry. I wouldn't want to fly on any plane that is running on the latest-generation Intel chips - they're just not settled yet.