Debris spotted by planes 650km off Brazil's coast belongs to a missing French airliner, officials confirmed on Wednesday.
The Air France plane carrying 216 passengers and 12 crew left Rio de Janeiro on Sunday night bound for Paris, but dropped off the radar a few hours into the flight.
A search plane on Wednesday saw a band of wreckage in a 5km strip in the Atlantic Ocean, Brazil's Defence Minister Nelson Jobim said.
A Brazilian navy ship is expected to arrive in the area soon to begin the grim task of recovering the wreckage amid bad weather. A French research ship equipped with two mini-submarines is also heading to the area to assist.
Officials predicted the hardest task would be finding the flight data and voice recorders that hold clues to why the Airbus A330 fell out of the sky during a severe storm on Sunday night. They promised a thorough investigation, but said the circumstances were very difficut.
Air France Flight 447 left Rio de Janeiro at 7pm local time on Sunday and lost contact with air traffic controllers early on Monday. It was scheduled to land at Charles de Gaulle airport in Paris at 11.15am on Monday.
The plane was carrying 216 passengers of 32 nationalities, including seven children and one baby, Air France said. Sixty-one passengers were French citizens, 58 Brazilian and 26 German. Twelve crew members were also on board, including three pilots.
It is Air France's worst disaster in the airline's 75-year history.
So far no bodies have been sighted on flyovers by the Brazilian air force, which spotted evidence of the catastrophe on Tuesday, allowing the navy to mount a retrieval operation.
Helicopters will be used to take wreckage of the Airbus from the ships to a base on the Brazilian archipelago of Fernando de Noronha, 700km from the crash site.
Black boxes may solve mystery
The black boxes aboard the missing Air France jet can survive as deep as 6,000 metres underwater and emit a signal for one month, according to French air disaster investigators, but none has ever been found this deep in the ocean.
Officials said the recorders needed to identify the causes of the mysterious crash could be on the ocean floor at a depth of up to 3000 metres. They are designed to send homing signals for up to 30 days when they hit water but many do not float well.
Authorities were at a loss to explain how a storm could have caused the plane, operated by three experienced pilots, to crash without sending a mayday call.
Air France said a lightning strike could be to blame and that several of the mechanisms on the Airbus 330-200, which has a good safety record, had malfunctioned.
But aviation experts said lightning strikes on planes were common and could not alone explain a disaster. They said the plane could have suffered an electrical failure, effectively leaving the pilots "blind" and making the plane vulnerable in an area notorious for bad weather.
Brazil's air force last had contact with Flight AF 447 about four hours after it took off from Rio when it was 565km from the coast. The last automated signals, which reported an electrical failure, were received about 40 minutes later.
Two Lufthansa jets believed to have been in the same area half an hour before the Air France mishap could provide clues for investigators, the World Meteorological Organisation said.