The so-called “black box” is one of the most important pieces of forensic evidence following a plane crash. There are actually two of these remarkably sturdy devices.

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?

Investigators found the recording devices, or black boxes, from the American Airlines plane that collided with a helicopter Wednesday near Washington.