Which was the last Boeing crash that didn't send its black boxes back to the US? I couldn't find an answer online, so I am asking the community.



The real question is how frequent it is for a Boeing crash not to send the black boxes back to the USA, and a reply to title's question would be a good basis for the real answer.

My feeling was the black boxes were sent back to the US for analysis (maybe I watched too match Mayday).

Article(s) mention that sending the data recorders to the USA would be to allow a party with a vested interest to be a judge in its own case, but this, I imagine, could be the case in older incidents too - but my feeling that wants the Boeing black boxes to be sent back to US invalidates the article's argument.
Please refer to the following website for more details

https://slate.com/technology/2019/03/ethiopian-airlines-737-max-black-box-sent-to-paris-why.html

The International Civil Aviation Organization, which sets the standards for aircraft accident investigations, says that the country where an incident occurs is in charge of the investigation

If the concerned country has the tool to analyse the black boxes, they are analyzed locally and if necessary with the help of the aircraft manufacturer, therefore

When the concerned country has the knowledge to do the analysis there is no point to send the boxes to the manufacturer country.  What is particular to the Ethiopian case is that even though not having the tools to do the Analysis they preferred the help of a third party, rather than sending the boxes to the US, but this is beyond the scope of the question.

So the Ethiopian government asked Germany to analyze the black boxes, but according to CBS, the Germans also lacked the necessary software, consequently Ethiopia asked the help of France, thus the boxes have been sent to the Bureau of Enquiry and Analysis, the BEA.