If the wreckage is located, and if any of it can be salvaged, there is a strong likelihood that there will be a stopped timepiece displaying the moment of impact.
That will then lead to a timing of events in terms of communications. This may even give further indications of where to look for more information, such as radar tracks.
Does that even work with quartz movements? Certainly not digitals. Or with water-resistant housings?
How likely is it that any of the passengers were even wearing mechanical watches? Who even does, anymore?
I do, every day. I assume many business travelers would do so as well.
Was there a Swiss passenger?
Mechanical Hand watches, even if electric (especially if electric) will stop when the watch is immersed (or when it hits 33m, depending…)