PARIS — French investigators on Tuesday recovered the cockpit voice recorder from an Air France flight that plunged into the Atlantic Ocean almost two years ago, killing all 228 people on board.

The machine that records cockpit conversations was located Monday and raised from the ocean depths on Tuesday, according to BEA, the French agency that probes air accidents.

The plane’s flight data recorder was pulled out on Sunday, meaning both pieces critical to determining the cause of the June 1, 2009 crash have now been found. The memory unit was found by a submarine probing (12,800 feet) 3,900 meters below the ocean’s surface.

Experts have said without the two recorders there would be almost no chance of determining what caused the worst disaster in Air France’s history. Flight 447 from Rio de Janeiro to Paris slammed into the Atlantic northeast of Brazil after running into an intense high-altitude thunderstorm.

The condition of the instruments was not immediately clear. BEA officials have warned that the recordings may yet prove unusable, considering the pressure they were subjected to for nearly two years at such ocean depths.

“We can’t say in advance that we’re going to be able to read it until it’s been opened,” a BEA spokeswoman told The Associated Press in a telephone interview. She did not give her name in accordance with her agency’s policy.

Automatic messages sent by the Airbus 330’s computers showed the aircraft was receiving false air speed readings from sensors known as pitot tubes. Investigators have said the crash, in a remote and deep area of the Atlantic, was likely caused by a series of problems and not just sensor error.

Air France CEO Pierre-Henri Gourgeon called the find “yet another decisive step forward in the inquiry.”

“It is my heartfelt hope that the data contained in these flight recorders may be used and provide answers to questions that relatives of the victims, Air France and the entire airline industry have been asking for nearly two years about why this tragic accident occurred,” Gourgeon said in a statement.

The flight recorders were recovered during a fourth search for bodies and aircraft debris. Investigators targeted an area 3,900 square miles (10,000 square kilometers), several hundred miles off Brazil’s northeastern coast.

In early April, French officials said the operation had found most of the Airbus jet, including its motors and more bodies of crash victims.

Determining the cause of the crash took on new importance in March, when a French judge filed preliminary manslaughter charges against Air France and planemaker Airbus.

Air France and Airbus are financing the estimated $12.5 million cost of the latest search effort, but the French government is paying for the recovery of anything that is found. About $28 million has already been spent on the three previous searches.