If the aircraft has ACARS (which I am sure it must have) then a report of height, speed and position is reported every minute
In which case the reported loss of contact time must be incorrect.
If Brazilian authorities are searching that part of the Atlantic, then we must assume that AF have passed on any flight data they have to the Brazilians.
If a catastrophic failure, then position data received every minute would provide a location accurate to +/- 10 miles.
SoS