Unsafe until the AoA instrumentation is made triple redundant (as on the Airbus). And all the avionics hardware and software is updated accordingly.

I believe there's still the fundamental aerodynamic/hardware issue of excess trim required to bring the plane out of the sort of event that a properly working MCAS would entail.

To actually fix this probably would be such a major re-design that all existing frames would have to be scrapped.

AC should ship 'em all back, and lease enough of an A320ceo fleet to get them through till they can get new built A320neo. With the recession that's unfolding, this should be less of a problem than anticipated between reallocating North American 737/320 fleet sorties to Rouge and Mainline widebodies, opportunistically picking up cheap leases, and delaying E90 fleet retirements.

It always was a dumb idea for AC to go with the 737Max, given that the A320's wider cross-section was a key differentiating feature between AC and its Canadian competition. All the alleged 'savings' arising from the cheaper up-front purchase price are almost certainly gone for AC now (although thankfully no loss of life on AC aircraft, although many Canadians fell victim to such on other airlines.)