Originally Posted by
Neo380
The word is there were no fallbacks. So, assuming that’s correct, the options don’t look good:
a. Not possible, you can’t build without fallbacks and say a crash can’t happen, NATS was living on hope (and tbh, tempting fate)
b. Ditto, as the system was never fully stress
tested
c. What controls; there were no fallbacks (tbc)?
Conclusion, the headline’s fully justified. Let’s see.
We don't know which system it was yet but apparently it had no fallback and wasn't stress tested?
We don't know if operating at its limits was an issue so the latter point may or may not be relevant. We know the number of atomic functions was the issue in 2014 but that limitation is unique to the NERC system and different boundary conditions apply elsewhere in the Flight Data thread. We don't know which system so how do we know whether those conditions were tested?
We know any fallback was ineffective but not what it was. I would expect the first level to be provided by an identical system because that is normal in this thread. I'd expect the last fallback to be manual fallback. We don't know what if anything was expected to happen between those.