Dozens of people are dead after a regional jet collided with an Army Black Hawk helicopter Wednesday night over Washington, D.C., officials said, the nation's first major commercial airline crash since 2009.

What is a black box, what can it tell us, and have the data recorders been found from Flight 5342 and the Army's Blackhawk?

As the plane made its approach to runway 33, an orange fireball lit up the horizon when the military chopper collided with the regional jet.