This data point is one of several key mysteries investigators are exploring as they seek to explain what caused the nation's worst air disaster in more than a decade, aviation experts said.

In the three years before the deadly collision between an Army helicopter and an American Airlines flight near Reagan ...

The collision of a U.S. Army helicopter and an American Airlines plane over Washington D.C. has left many people stunned.

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An Army Black Hawk helicopter collided with a regional jet near Ronald Reagan Washington National Airport on Wednesday evening, U.S. officials confirmed to ABC News.

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The search and rescue mission was transitioning to a recovery mission, and no survivors were expected, DC Fire and EMS Chief ...

A deadly collision on Wednesday night between an American Airlines plane with 60 passengers and four crew and an Army UH-60 ...

Transportation Secretary Sean Duffy, who was sworn in earlier this week, said on Thursday both an American Airlines passenger jet and a U.S. Army helicopter were in standard flight patterns before ...

The initial focus of the military investigation is on the altitude of the helicopter at the time of the crash and the ...

" Trump suggested the goggles, if worn, could have played a significant role in the accident. The mission was a ...