Heres the latest.
A Dutch ship towing a high-tech US Navy listening device is trawling the Atlantic for data and voice recorders that investigators say are key to determining what caused an Air France jet to crash with 228 people on board.
The navy device, called a Towed Pinger Locator, will try to detect emergency audio beacons, or pings, from Flight 447's black boxes, which could be lying thousands of feet below the ocean surface.
Without the recorders it may be impossible to know what caused the Airbus A330, which had five Britons aboard, to crash several hundred miles off Brazil's north-eastern coast.
The locator device is capable of searching to a depth of 20,000 feet. The first of two devices was towed in on Sunday by a Dutch ship contracted by France.
US Air Force colonel Willie Berges, commander of the American military forces supporting the search operation, said the locator device would start operating as soon as searchers were sure it would not interfere with a French nuclear submarine already searching for the black boxes.
Another Dutch ship carrying a second listening device will arrive later on Monday.
The ships will tow the locators in a grid pattern while 10-person teams watch for signals on computer screens.
The search area includes some of the deepest waters of the Atlantic and in two more weeks the boxes' signals will begin to fade.
In Paris, the head of Airbus's parent company said there was probably more than one reason for the crash.
"In such an accident there is not one cause," EADS chief executive Louis Gallois said. "It's the convergence of different causes creating such an accident. It's essential for everybody to know what happened and we know that it's not easy. I hope we will find the black box."
