The crash site of Germanwings Flight 9525 in the French Alps. Evidence from the flight data recorder shows the co-pilot accelerated as the airliner headed toward the mountainside, French investigators say. BEA hide caption

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Mountain troops, police and gendarme officers listen during a briefing before heading to the Germanwings crash site Thursday in Seyne-les-Alpes, France. A French prosecutor said Thursday the plane's second black box has been recovered. Claude Paris/AP hide caption

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Andreas Lubitz competes in the Airportrun in Hamburg, Germany, on Sept. 13, 2009. Lubitz, the Germanwings co-pilot, is believed to have deliberately crashed his plane carrying 149 others into the French Alps last week. Michael Mueller/AP hide caption

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Airplanes' contrails streak the sky close to where a Germanwings plane crashed last week, in Seyne les Alpes, France. Thomas Lohnes/Getty Images hide caption

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Germanwings Crash: Co-Pilot Was Treated For Suicidal Tendencies
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A German police investigator carries a box after searching an apartment believed to belong to the crashed Germanwings flight 4U 9524 co-pilot Andreas Lubitz in Duesseldorf, on Thursday. Wolfgang Rattay/Reuters/Landov hide caption

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A stone memorial, surrounded by flowers, has been placed near the site in the French Alps where a Germanwings passenger jet crashed on Tuesday (March 24, 2015). Investigators believe the jet's co-pilot brought it down deliberately. Jeff Pachoud /AFP/Getty Images hide caption

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Germanwings Crash: 'Suicide' Doesn't Seem To Tell The Story
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A Southwest Airlines pilot and co-pilot preparing for a flight from Dallas last year. In the wake of the Germanwings crash this week, many European airlines are rushing to adopt a two-person cockpit rule similar to the one already in place in the U.S. LM Otero/AP hide caption

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Police officers carry boxes outside a house in Montabaur, Germany, on Thursday in connection with the investigation into the Germanwings A320 crash. Fredrik von Erichsen /EPA /Landov hide caption

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German policemen stand outside a house believed to belong to Andreas Lubitz in Montabaur, Germany, on Thursday. Lubitz, the co-pilot on the Germanwings plane that crashed Tuesday, is suspected of deliberately crashing a the jet into the French Alps. Ralph Orlowski /Reuters /Landov hide caption

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An image from AFP TV video taken Tuesday shows smoke billowing from scattered debris of the Germanwings Airbus A320 at the crash site in the French Alps above the town of Seyne-les-Alpes, France. Denis Bois/AFP/Getty Images hide caption

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Students mourn in front of their school in Haltern, Germany, on Wednesday, a day after the Germanwings plane crash. Sixteen high-schoolers and two teachers from the school were among the 150 people onboard the plane. Martin Meissner/AP hide caption

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