As far as I can tell, the following factors all contributed to this crash:
- Pitot tubes susceptible to ice crystal blockage
- Crew not aware that they can stall the airplane due to alternate law
- No return to normal law after reliable speed information was available to the flight computers
- "Unlinked" sidesticks which allow the pilots to command different inputs, unaware of what the other pilot is commanding
- Stall warning goes quiet when the airspeed is too low
Of these, the first factor (pitot tubes) was already in the process of being mitigated. What about the other factors though? Were the onboard systems modified in any way to fix these shortfalls?
I'm no expert but it seems like at the very least that the following would help:
- If the stall warning didn't stop, but instead changed into an even more ominous "you're now tumbling down at less than 60 KIAS" warning.
- Also, given how extremely rare alternate law appears to be, it might not be out of order for the airplane to announce that it is now very much possible to stall the plane by pulling up (in actual words).
- Finally, it sounds like the unlinked nature of the sidesticks was a big part of the problem; are there good reasons to leave them unlinked in future designs?