From Airbus A319/320/321 FCOM:
The cockpit voice recorder (CVR) records :
‐ direct conversations between crew members in the cockpit
‐ all aural warnings sounded in the cockpit
‐ communications received and transmitted by radio
‐ intercommunications conversations between crew members
‐ announcements transmitted over the passenger address system, if PA reception is selected on the
third audio control panel.
Only the last 2 h of recording are retained.
The CVR system consists of :
‐ a remote microphone behind the overhead panel
‐ a “hot mike” function, which records the crew members voice directly from their microphone, even
if the push to talk switch is not activated.
‐ a crashproof four-track recorder, equipped with an underwater locating beacon, in the aft section
of the aircraft
‐ a control panel on the overhead panel.
It is energized automatically :
‐ on the ground during the first 5 min after the aircraft electrical network is energized
‐ on the ground with one engine running
‐ in flight
On the ground, it is stopped automatically 5 min after the last engine shutdown provided the CVR
jack is not used.
On the ground, the crew can energize the CVR manually by pressing the GND CTL pushbutton
The Flight Data Recording System, which records the mandatory parameters, consists of the
following components:
‐ A Flight Data Interface and Management Unit (FDIMU)
‐ A Digital Flight Data Recorder (DFDR)
‐ A three-axis Linear Accelerometer (LA)
The FDIMU collects and processes parameters from the SDACs, DMCs, FWCs, FCDCs, BSCU, the
DFDR event pushbutton, the GND CTL pushbutton and the Clock.
It stores the mandatory flight parameters in the DFDR.
The DFDR can store the last 25 h data, at least. It stores this data on a fireproof and shockproof
device. An underwater locator beacon is attached to the DFDR.
The linear accelerometer measures the acceleration of the aircraft along each of the three axes.
The QAR is an operational recorder that stores the same data as the DFDR. However the QAR is
more accessible for the maintenance crew.
The recording system is automatically active:
‐ On the ground, during the first five minutes after the aircraft electric network is energized.
‐ On the ground, after the first engine start.
‐ In flight (whether the engines are running or not).
On the ground, the recording system stops automatically five minutes after the second engine shuts
down.
