French investigators have detailed initial plans for a third attempt to find the wreckage and flight recorders from the Air France Airbus A330 lost over the South Atlantic in June 2009.
An international team has been trying to narrow the search zone, through oceanographic and meteorological considerations, and has selected the equipment that will be used in the search.
The search team has had to rely on additional data and obtain better estimates of currents and drift effects to refine its results.
France's BEA investigation agency says that the modelling work to determine the search zone has "reached the limits of current knowledge".
BEA adds that the zone will be optimised and revised once the operation starts in mid-March.
Two search vessels - one from Norway's Seabed Group and the other from US underwater engineering specialist Phoenix International - have been recruited for the attempt.
These will be complemented by three autonomous underwater vehicles, two remotely operated vehicles and a deep-towed sonar.
A French naval patrol vessel will be stationed at Cayenne and used to transport the flight recorders if they are recovered.
Neither recorder has been found despite a month-long search, from 10 June to 10 July last year, to detect their acoustic locator beacons, and a follow-up search for the wreckage, from 27 July to 17 August, using towed array sonar.
Air France flight AF447 crashed while en route from Rio de Janeiro to Paris on 1 June 2009.
Source: Flight International