SaturnV;
I don't know AF procedures, but in this instance, AF OCC sent an ACARS message to AF447 after 04h00 requesting it contact a control center. Would the usual AF procedure be for the crew of the receiving aircraft to acknowledge receipt of such a message? If so, would not AF OCC then be looking for confirmation of message receipt, and if there were none, try to re-contact or go on heightened alert re: AF447?
A crew receiving an ACARS message from company may or may not acknowledge, and a lack of acknowledgement
at that time, would not necessarily be reason for concern. The unfolding process is, as you decribe, on pages 42 through 44 of the BEA Report. AF first began enquiries at 05 h 50 and it unfolded from there.