Cockpit Voice Recorders

Procedures and regulations are made by authorities, with the only one goal which is the inscreased in safety of flight operations. They are made from experience coming sadly from the past accidents or incidents. Investigation department has shown the advantage of having a cockpit voice recorder on board an aircraft.
If they are not part of the active systems fitted to help the crews to avoid any accident or incident, they are part of the main way to find out the series of events which happened during a flight before any accident or incident, and so provide authorities and operator a method to improve their procedures and/or requirements.

In the end, EU Ops define the requirements for the use of such systems.