Flight Data Recorders (FDR) – popularly referred to as an aircraft’s “black box” – typically store important data to crash-protected memory. These are often combined with Cockpit Voice Recorders (CVR) that log pilot and cockpit audio. The memory used to store this data is encased in layers of protective materials – orange paint (ease of visual location), stainless steel or titanium (to withstand shock) and high-temperature insulation (to withstand heat). This helps to ensure that in the event of an accident, data pertaining to the aircraft’s performance and pilot’s actions are available for investigators to analyze. FDRs began entering service on civil aircraft in the 1960s and the various environmental tests that a recorder’s crash protected memory have become more stringent over the years.