What is a black box anyway?
AirAsia flight QZ8501 (27 Videos)
What is a black box? Hear everything you need to know about the boxes that are key to every plane crash investigation.
By Ben Brumfield and Jethro Mullen, CNN
Search teams have now found four large pieces of debris believed to be parts of AirAsia flight QZ8501, the head of Indonesia's search and rescue agency announced Saturday.