so ACARS first, followed by ADSB failure followed by the radar. I wonder if there is any truth in that 'witness' report about seeing a fireball...
Initial reports of satellites seeing a heat flash have been walked back, so it's looking less likely that it was a sudden event (doesn't rule out incendiary device).
LA Times:
EgyptAir Flight 804: No explosion detected by satellites - LA Times
"U.S. reconnaissance satellites did not detect evidence of a large flash or explosion aboard the EgyptAir A320 jetliner, U.S. officials said."