"well founded fears"? The first crash was due to pilot errors (the previous pilots recovered airplane). The pilot errors were caused by lack of documentation (about a change), but still, by following old procedures, the airplane were recoverable; and an additional cause: the airplanes should have no flown again with know and reported recurring problem. So 3 sequential causes which now are known and corrected.

For one airplane, one case. There is never a single point of failure. Nearly all modern crashed are caused by a series of errors/problems. On the older case, there were issued notices to all pilots about the 3 errors that were made (maybe also more).

Without wanting to argue the point for the specific type that seems to have prompted this question: Who would be involved in determining what qualifies as "well founded fears of catastrophe"? The airline wouldn't be flying the plane if they agreed with your judgment, so presumably you're not getting anything from them. Likewise the EASA/FAA/other regional equivalent wouldn't allow the type to fly if they agreed.

It's not a technical debate about aircraft guys! It's an interesting question.

@GiacomoCatenazzi that the previous pilots recovered the airplane does not prove that pilot error was the cause of the crash.

@ThEiLlEgAlaLiEn I don't know why you think I'm accusing you of a money grab. Airlines don't give refunds or re-routings for nothing, and if the airline and regulators say the plane is safe then "nothing" is exactly the refund/re-routing reason you have from their perspective.

@Fattie I don't think anyone is debating about the aircraft; it's about "well founded fear" that the OP stresses. The point that is being made is "is it possible that one have a well founded fear of a specific aircraft that is still in service" - because if it's a well founded fear, then the regulators should have required the craft to be taken out of service. (on re-reading, maybe they are... ) shrugs I don't know, time for coffee. I guess the follow up would be can you have a "well founded fear" of a specific airline.

Re your TLDR, I don't think it's unusual for an airline to ground their fleet of a kind of plane that just crashed. One could also suggest that China has a vested interest in the success of the Comac 919, a competitor of the 737-MAX that's currently under development. (I'm not sure if that's a reasonable suggestion.)

@ThEiLlEgAlaLiEn On the other hand, the fact that ten out of sixteen airlines that own 737-MAXes are continuing to fly them suggests that this fear might not be so well-founded. (The exceptions are Ethiopian, and four airlines in China and one in Indonesia, who've been ordered to ground their planes by their regulators. )

@DavidRicherby When the issue at hand is life and death, you think approximately 67% confidence (using the term loosely) are good odds? Lol really? One learns a new thing every day.

@ThEiLlEgAlaLiEn That's such a loose use of the term that it's meaningless.

@DavidRicherby Your conspiracy theory is not reasonable. It's extremely far-fetched and reeks of anti-Chinese racism. Ethiopia Airlines also grounded their 737 Max's, so maybe you want to have a go at Africa while you're at it.

Given that two of the aircraft have, recently, crashed killing everyone the idea of debating whether fears are well founded is just - ridiculous. OF COURSE fears are well-founded - the aircraft company and the various national authorities are desperately investigating. CHINA HAS BANNED THE AIRCRAFT! Good grief. Of course any fears are 'well founded".

The question is a great question - at boarding, if you refuse to fly (say .... because of two major recent catastrophic crashes) can you get you money back. Getting hung-up on the phrase "well-founded" is really an irrelevancy.

@DavidRicherby You very likely would have found the fear well grounded if it was British Airways grounding its fleet. I wouldn’t be surprised.

A Dutch airline (not KLM by the way) announced today that people who refuse to fly in one of their planes will not get any compensation. And I guess they will not be the only company in the world.

@Fattie getting hung up on whether this particular instance constitutes a well-founded fear might be irrelevant, but the "well-founded" part's really not an irrelevancy at all, as it's absolutely fundamental to the premise of the question. Everybody accepts that if you turn up and decide not to fly because the pilot's called Dave and you don't like that name, you're not getting anything from anyone. But to answer whether a "well-founded" fear changes that, we first have to know what qualifies a fear as "well-founded".

@Fattie as I said earlier, it can't be up to the airline or the regulatory body, as they wouldn't allow the flight to go ahead if they agreed that the passenger's "fear of catastrophe" was well-founded.

@Willeke Ah KLM and the Dutch. The deadliest plane crash in history was caused by a Dutch KLM pilot and to this day they Dutch transportation safety board refuses to accept that fact.

@ThEiLlEgAlaLiEn My "ten out of sixteen airlines that own 737-MAXes are continuing to fly them" was based on reporting by the BBC earlier today. They now report that ten airlines have grounded their 737 MAX-8s, fourteen have not and lists a further twelve "Other airlines that use the 737 Max 8". Honestly, I have no idea what those numbers are supposed to mean since, earlier today, they explicitly said that 16 airlines have taken delivery of MAX-8s...

... and now they're mentioning 36 airlines.