@ portmanteau
Well it looks like they were able to derivate a very close position of the crash site from 5 satelite pick up of two short beacon bursts at 00:36z. A previous report mentioned that those data were treated by Airbus (or Space Agency in Toulouse) for Egyptian authorities. The Gardian wrote something that is looking accurate yesterday:
Distress signal from EgyptAir flight 804 confirmed by authorities in Cairo and US | World news | The Guardian