Engineers?
I am not questioning the current airworthiness, I understand the issue has been addressed. I don't think that the system was airworthy at the time. What I am saying is, if they were known to be junk Airbus had an obligation to have an AD issued to insure they were changed out and they didn't do it until after this crash.
It's easy to find fault but not easy to find perfection.
Like all systems, even with those with redundancy, it is necessary to assume failure conditions. So the pitots fall off due to birds hitting them or clogged up in volcanic ash or even ice up because the heating system fails. There should be a presumption of some sort of backup to fly the plane to the nearest airport.
From my read this presumption was met
The problem with assumed failure rates is the limited verification that they are valid to within a 10 power magnitude. This comes about by both certification standards as well as historical experience under wide ranging conditions.
I can't yet find fault with the design assumptions in this instalation. The certification was valid as well based on what was known at the time.
But there is a problem to be further explored.
Once the actual failure rate becomes obvious in the historical useage of the system (they iced up more often than expected) then the system interaction with the ability to continue safe flight and landing needs to be examined. From my read so far, that includes the crew actions and their failure rate (to take appropriate action). I really don;t know how this was taken into account (presumably it was at least considered).
If the crew failure rate combined with the pitot failure rate was taken into account then supposedly the risk should have been minimized to a reasonable level. Somewhere in all this is where the corrective action should have been taking place.
I don't see how you can fault Airbus for not mandating a balance between all the contributors since all they can do is recommend a course of action based on their own knowledge. Anything the operator does in the use of the product is outside of their ability to control.
I think it's best to let the BEA investigation identify the critical paths and develop recommendations accordingly.