I’ll take the one with 50 crashes any time. That’s 50 times something went catastrophically wrong and 50 times measures were taken to fix the underlying problems.
A brand new plane will undoubtedly have brand new problems.
I think this is the wrong take, for the following reasons:
- There is no reason to assume that the learnings from the 50 crashes weren't also applied to the newer model. In fact you'd expect that they all were.
- Faults in a new design are likely to be front-loaded, meaning most of the crashes would have happened earlier than later. Therefore the new model seems to be a much safer design if it flew 10% of the miles without even 10% of the crashes (actually 0%).
The point is that commercial aviation is so extraordinarily safe, that mechanical failures that result in fatalities are too rare to determine if a model with 5 million flight hours is more or less safe than another model with 500 million flight hours.
Zero fatalities does not mean the aircraft is statistically safer unless it has an order of magnitude more flight hours.
I'm not sure if I agree or not, but my thinking were that it wouldn't reach great safety by upgrades until long after it became too expensive for Boeing and would instead be replaced with a new model.