Kirk watching Spock and McCoy on the flight recorder
A flight recorder was used for recording footage of both the interior and exterior of a starship. These recordings allowed a person to playback that which was recorded for the purpose of conducting investigations.
In 2285, Admiral James T. Kirk and Sarek reviewed the USS Enterprise's flight recorder to observe Spock mind melding with Doctor Leonard McCoy, which transferred his katra into his body. (Star Trek III: The Search for Spock)
In 2368, Nicholas Locarno told Wesley Crusher that his flight recorder was so badly damaged after a Yeager loop near Titan that only a third of the telemetry was able to be retrieved. (TNG: "The First Duty")