I'm wondering if the preflight planning or any discussions the crew had preflight might reveal the start of the chain that caused them to accept the flight plan.They must have studied the ITCZ wx and based their plans on that.
1. Would a flight plan rerouting direct to say west Africa then north be unavailable to 2 engine ops due to the long overwater leg ? Maybe not.
2. This leaves an alternate route to the north west of South America, with an enroute fuel stop which may have flightime limitations or even be impossible to reroute around the ITCZ considering its forecast size.
3. Have a go using radar to find a hole in the ITCZ. Maybe closer inspection will see if AF447 made any deviations. Nearest airways are along way away (UN866 and UB623). Crews turn off airways for a few miles without contacting ATC in a non radar environment. Especially allowing for the hassle of using HF radio when flying the aircraft is priority No.1.
4. If no luck in getting through then the possibility of dropping into Recife ( an AirFrance station in my days) for a replan.
SFD