Boeing didn't ground the plane before the 2nd crash. In Nov 2018 shortly after the 1st crash, in a meeting with American Airlines Pilots Union pilots, Boeing refused to ground the plane, yet they knew there was a problem:https://www.nytimes.com/2019/05/14/busi ... crash.html
That is correct, and it is old news. They knew repeated MCAS activations were a factor in the crash, but Boeing and global regulators did not appear to believe the situation was radically different from other potential upsets flight crews should be capable of recovering from, so they issued information on what MCAS system does and how to disable it. Unfortunately, even with that information, the crew of the Ethiopian flight still crashed. I'm going to stop there rather than reignite the debate on what the crew of the 2nd crash might have done differently.
From a high level perspective, it doesn't matter what the flight crew might have done differently. What matters is it once the data showed that MCAS had been involved in the Ethiopian crash as well, it was clear that the Lion Air crew's difficulty dealing with MCAS malfunctions was not unique. The assessment of low risk of continued operation with better information for crews who may face the issue had not borne out.
Again, mixing words with actions. If Boeing's actions represent dominos, we have an odd coincidence of dominos lining up perfectly with Max design and certification processes, regardless of what Boeing and the FAA said after they got caught.
You're not making clear what your point is. We know there was a coincidence of circumstances lining up to lead to the crashes despite multiple layers of safety. That is the case with most crashes and not in question here.
The words and the actions are consistent, but based on flawed information. After the first crash, Boeing and the regulators believed the plane could be operated safely despite the issue if crews were more explicitly aware there could be a need to follow a runaway stabilizer procedure as an interim mitigation until a permanent fix was ready. Those was their words. They allowed it to continue operating after the Lionair crash. That was their action.
The real problem is the mistakes in the risk analysis that concluded pilot actions to counter a fault were reasonable and sufficient for the conditions that would be present if a fault occurred. That led to the conclusion redundancy was not required in order to prevent a fault, rather than just assure it was rare. They also failed to re-analyze the risk as the design evolved to allow more stabilizer travel due to MCAS. Those mistakes were not resolved when the grounding questions were first asked, so the same mistaken risk analysis led to the same mistaken conclusion.
When the second crash happened, they limited their words for 2 days while they started the action of collecting and analyzing the data. The media, writing to an audience that doesn't even understand simple words like "literally," had no difficulty spinning the FAA's technical words that they hadn't determined "systemic performance issues" as if the FAA were declaring summarily that there was no problem. A few less official comments were actually rather dismissive, but those comments were not the basis of the FAA decisions. However, the actual text of the [url="https://www.faa.gov/news/updates/media/CAN_2019_03.pdf"]CANIC[/url] issued the day of the accident indicated they were investigating what the problem is and whether it was related to the previous crash:
External reports are drawing similarities between this accident and the Lion Air Flight 610 accident on October 29, 2018. However, this investigation has just begun and to date we have not been provided data to draw any conclusions or take any actions.
Somewhere around 2-1/2 days after the crash, before the flight data recorders had even been read, but once they had a look at the elevation data broadcast by the aircraft, and received the report from the investigators on the ground that the horizontal stabilizer jack screw was in an extreme nose down position, they concluded the evidence presented significant concern the crashes were related, and they grounded the MAX.