The French accident investigation board, known by its acronym BEA, will commence Phase 2 of the search using sonar and diving equipment from a French research vessel to scan the mountainous ocean floor for any signs of wreckage and the plane's flight data recorders.
The initial search, which focused on locating the "pinger" signal emitted by the black boxes, ended July 10 after the batteries which power the signal were thought to have run down.
This new phase of the search, which will use a towed sonar system to scan the ocean floor, is expected to last a month.
"If we are very, very lucky, we will find [the flight data recorders]," says Martine Del Bono, a BEA spokeswoman. "Right now it's step by step in the investigation, so we are in the beginning of Phase II. After that, we'll see."
The flight data recorders, also known as black boxes, hold key information that can help explain what caused the Airbus 330-200 to plunge into Atlantic Ocean in a thunderstorm on a routine flight from Rio de Janeiro to Paris. All 228 people aboard are believed to have perished. Aviation analysts say it's vital to find the black boxes and as much wreckage as possible in order to understand what caused the accident – so that others can be prevented.
They also note that it's rare for black boxes not to be recovered, even in ocean crashes. That's in part because most accidents occur either on landing or take off, so the wreckage is usually in relatively shallow water. In this case, investigators must search more than one hundred miles, and the remaining wreckage is believed to be two to three miles underwater.
"This represents some of the most severe challenges that investigators have to deal with in an underwater recovery, given there's a very large search area which is very deep with a very rugged terrain," says Frank Hilldrup, an accident investigator with the National Transportation Safety Board in Washington.
More than 640 pieces of wreckage have been recovered so far including an almost-intact tail section, an engine cover, life jackets, seats, and kitchen items. These pieces arrived in France this week and will be examined by the Toulouse aeronautical test center, under the control of senior police officers from the Air Transport Gendarmerie and investigators from the BEA, the French investigation board said in a statement.