We've now exceeded 200 posts per grounded UA aircraft. Congratulation FT!

Good riddance!

The number of deliveries is irrelevant. If you want to measure risk, this should be accidents or fatalities per flight or per flight-mile or per passenger-mile. I really don't know what the delta is for this -- I'm sure the numbers are available for calculation -- but the fact of zero accidents of this nature when flown by US pilots or by companies with stricter training standards does stand out. Were there just comparatively fewer flights/flight hours/flight miles so there wasn't as much opportunity for problems to arise or was it that the problems that arose never became problems for trained and experienced pilots?

MCAS appears to have made a bad problem worse but the facts are 1) the flights were already in trouble before MCAS became an issue, 2) the pilots did NOT follow proper procedure for runaway trim, 3) following decades-old procedures for runaway trim would have rendered MCAS moot.

Even if you accept Airbus's central design premise of engineering for the plane to essentially fly itself while the pilot is just there to assist in take-offs and landings versus Boeing's traditional premise of designing for pilots, we should be concerned about the pilots being overwhelmed and exceeding the flight envelope at take-off.

Well, there were zero accidents of this nature OF ANY KIND, INVOLVING ANY AIRCRAFT over the past 10 years when flown by US pilots. So the standard is very, very high. That's why two accidents, anywhere in the world, involving the same plane model, within 10 months of each other, is so unnerving.

Success in safety inevitably begets ever-higher expectations. The expectation among most passengers these days is that planes don't crash. Ever.

At the time of the grounding I believe WN was the largest single operator and AA was #3 . I would call that relevant information.

I am often forced to fly bad airlines that have bad pilots. As such, I hope that we are flying on planes that don't require expert "airmanship" in order to prevent disasters.

You're forgetting the Colgan disaster just because it's a few months outside of 10yrs? A horrific accident due solely to the blatant incompetence and lack of training and experience of US pilots?

Is knowing a decades-old procedure supposed to be "expert"? Is turning the manual trim wheel in the correct direction supposed to be expert? The two flights in question appear to have already been in trouble before MCAS was activated.

Luckily they manage to stop those US pilots who are drunk well before they start the plane. Often outside the US.

Based on what?

The accident reports.

You definitely don't want to measure it by flight-mile or passenger-mile. Deaths on a longhaul flight are equally bad as deaths on a shorthaul flight.

The facts are never that simple and there certainly are many more than you've listed. One thing I think we know is that there never had been a runaway trim of this type before... one where the computer keeps activating it (radically) over and over. At least none that's been mentioned. So it might be that procedures can deal with this type of event but if the event is totally new then it adds a whole other dimension, especially when Boeing didn't really tell anyone about this "feature" beforehand (in the case of the Lion Air crash).

I haven't seen anything about either accident to indicate that had MCAS not been fitted to the aircraft they would still have crashed.

Nor will you. Nothing anywhere says that. The debate is about when the MCAS system created a deadly situation if the pilots should have (a) figure out it was the MCAS system, and (b) fixed the issue by the runaway trim procedure. The question is if the pilots should have reasonably have been expected to resolve the issue created by MCAS.

I don't have a strong view on this, other than to say that if it was as simply as some suggest, then after two MCAS system crashes - and every 737 pilot being well aware of the issue, their ought to be no reason to change the plane, right? It is safe to fly today, as is.

The fact that no one in any possition of authority, not even (at this point, it was their earlier view) Boeing, is making that arguement.

And of course, the FAA found other issues with the planes computer systems in testing in June of 2019.