The attack sub Emeraude plans to trawl 35sq km a day, using sonar to try to pick up the boxes’ acoustic beacons or “pingers,” French armed forces spokesman Christophe Prazuck said yesterday.
It’s a race against time, because the beacons will start to fade 30 days after the May 31 crash.
If the boxes are spotted the Emeraude will work with the mini-sub Nautile, which can descend to the ocean floor and was a key part of the search for the Titanic.
“There are big uncertainties about the accident site, the ocean floor is rugged... so it’s going to be very difficult,” Prazuck told France-Info radio. “It’s going to be very complicated and we’re going to need a lot of luck to find the black boxes.”
The French submarines will be aided by two US underwater audio devices capable of picking up signals even at a depth of 20,000 feet (6,100 metres). One of those was being loaded yesterday onto a ship off Brazil’s northeastern coast.
A total of 41 bodies have been recovered so far from the scene of the crash, about 640km northeast of the Fernando de Noronha islands off Brazil’s northern coast. The remains are being flown daily to Recife, where investigators hope to identify them and uncover clues into the crash based on the victims’ injuries.
Without key information from the Airbus A330’s missing data recorders, investigators have focused on the possibility that external speed monitors – Pitot tubes – iced over and gave false readings to the plane’s computers as it flew into thunderstorms.
Airlines around the world have begun replacing Pitot tubes on their aircraft. And the European Aviation Safety Agency, responsible for the certification of Airbus planes, said it was “analysing data with a view to issuing mandatory corrective action” following reports about the possible malfunctioning of the Pitot tubes. But it said the A330 and other Airbus aircraft are safe to operate.
Air France said it began replacing the tubes on its A330 and A340 jets in May after pilots reported several incidents of icing leading to a loss of airspeed data.