Originally Posted by Outsider

So, I have a question.
The media is reporting that "authorities" have specific times that the Xpndr and ACARS were "turned off".
How the hell do the "authorities" know this?
My understanding is; they were not in radar contact at the time and unless ACARS was in the middle of a transmission, I don't know how they could know these times so specifically.
Am I missing something here?
Also if ACARS is off, what system is pinging the satellites?
I'm old but I don't get this.

Graybeard