Bearfoil
Looking carefully at this comms sequence, and the blasé approach to ATC procedures which started way back in Rio de Janeiro when the Flight Plan wasn't transmitted to Dakar, you'd be forgiven for thinking that the outcome of the flight was doomed from the start.
Forget all that and just assume that AF447 was trucking along in its own little world, and they suddenly decided they wanted to share some bad experience with aircraft in their vicinity. Well, in their case they had 3 Air France aircraft all well within VHF radio range at 0212z -
- and it would appear they didn't avail themselves of the opportunity on 121.5 or 123.45MHz. The "why" or "why not" lies on the seabed somewhere out there, and what the recorders eventually reveal may be somewhat different to all the hypothesis expounded here.
NOTE:: The radius of each of the circles above is a nominal 250NM to the horizon at FL350, and in theory comms would be possible when the circumference of any circle had intersected another.
P.S. A little bit of background to the introduction of ADS-C procedures in the ATLANTICO and DAKAR OCEANIC FIRs can be found
here.
mm43