black box vs flight recorder

black box

noun
  • A flight recorder; the brightly colored cockpit voice recorders and flight data recorders in an aircraft designed to aid in determining the cause of an accident. 

  • A device used in phreaking that prevents the calling party from being billed for the call placed. 

  • A type of theater characterized by a lack of decoration or complex mechanisms. 

  • A theoretical construct or device with known input and output characteristics but unknown method of operation. 

  • Any similar device on motor vehicles, such as rail event recorders and ship trip recorders. 

verb
  • To focus on the inputs and outputs without worrying about the internal complexity. 

flight recorder

noun
  • A device which records data that would be of use in investigating the cause of an aircraft accident; usually in pairs, consisting of a flight data recorder and a cockpit voice recorder. 

How often have the words black box and flight recorder occurred in a corpus of books? (source: Google Ngram Viewer )