After finding the black boxes, investigators take the recorders to a lab where they can download the data from the recorders and attempt to recreate the events of the accident. This process can take weeks or months to complete. In the United States, black box manufacturers supply the National Transportation Safety Board with the readout systems and software needed to do a full analysis of the recorders' stored data.
If the FDR is not damaged, investigators can simply play it back on the recorder by connecting it to a readout system. With solid-state recorders, investigators can extract stored data in a matter of minutes through USB or Ethernet ports. Very often, recorders retrieved from wreckage are dented or burned. In these cases, the memory boards are removed, cleaned up and have a new memory interface cable installed. Then the memory board is connected to a working recorder. This recorder has special software to facilitate the retrieval of data without the possibility of overwriting any of it.
A team of experts is usually brought in to interpret the recordings stored on a CVR. This group typically includes representatives from the airline and airplane manufacturer, an NTSB transportation-safety specialist and an NTSB air-safety investigator. This group may also include a language specialist from the FBI and, if needed, an interpreter. This board attempts to interpret 30 minutes of words and sounds recorded by the CVR. This can be a painstaking process and may take weeks to complete.
Both the FDR and CVR are invaluable tools for any aircraft investigation. These are often the lone survivors of airplane accidents, and as such provide important clues to the cause that would be impossible to obtain any other way. As technology evolves, black boxes will continue to play a tremendous role in accident investigations.