Well, sometimes they are box-like. Also, the “black box” that news reports refer to are really two separate items. Neither one is black.
The black box is made up of two items:
The flight data recorder (FDR) is a device that preserves the recent history of the flight through the recording of dozens of parameters collected several times per second. The cockpit voice recorder (CVR) preserves the recent history of the sounds in the cockpit including the conversation of the pilots. The two recorders give an accurate testimony, narrating the aircraft’s flight history, to assist in any later investigation.
The FDR used to be the only device, but they added the CVR in when technology got better.
Some of the original black boxes were black and box-like. But it seems like the pilots called them whatever they looked like on their particular aircraft.
Whatever the color, these devices are covered in fire-resistant paint–and are meant to be found easily. Thus, the orange now.
So why do they still use “Black Box?” The pilot interviewed by the Wall Street Journal believes it is because that term is “evocative”.
Some people think it’s because the black box is a black box to people (in the colloquial usage).
One explanation goes this way: In 1939, an aviation engineer named François Hussenot devised a means of capturing an aircraft’s history to a box of photographic film. Onboard sensors flashed into the box through calibrated mirrors and traced a running tab of flight parameters, including altitude, air speed and the position of the cockpit controls. Because the device worked like a camera, its insides had to be in total darkness; thus, perhaps, the “black”-ness of the box.
However it got its name, it is certainly not descriptive!
Either way, it’s lot easier to say “black box” than “orange box”.