French investigators have detailed plans for a fourth attempt to locate the wreckage of the Air France Airbus A330-200 lost over the Atlantic in mid-2009.
The Bureau d'Enquetes et d'Analyses says that Air France and Airbus will co-fund a $12.5 million hunt for the aircraft.
It will use resources from the Woods Hole Oceanographic Institution and use three Remus 6000 autonomous underwater vehicles from the specialist vessel Alucia.
Brazilian ports at Suape, Recife and Fortaleza have been identified by WHOI as base points from where the search will be mobilised.
The vessel is scheduled to leave Seattle on 9 February and arrive in Brazil on 14 March, departing for the first leg of the search on 18 March.
This will last about a month, while two other similar search departures are scheduled for 25 April and 2 June.
WHOI says that the area searched so far covers 7,000km² but that there is an unsearched area of interest covering 10,000km².
In its presentation today the BEA also says that it is making preparations to engage in a separate fifth phase of the operation, a state-funded recovery effort, if the hunt is successful.
Air France flight AF447 had been operating from Rio de Janeiro to Paris on 1 June 2009. Its flight recorders have not been recovered, and the accident remains unexplained although there is evidence that the aircraft suffered loss of reliable airspeed data while flying through storm clouds.