Govind D. Belgaumkar

MANGALORE: Cockpit voice recorders (CVRs), which are installed on aircraft, are expected to retain the information recorded during at least the last 30 minutes of their operation.

The Directorate General of Civil Aviation (DGCA) has defined the CVR as an equipment installed in the aircraft for recording the aural environment on the flight deck during the flight time for accident/incident prevention and investigation.

According to the DGCA notification effective from December 12, 1996, CVRs have to meet the prescribed crashworthiness and fire protection specifications. They should be capable of recording the voice communication transmitted from and received in the aircraft by radio; aural environment on the flight deck; voice communication of the flight crew on the flight deck, using the aircraft's interphone system; voice or audio signals, identifying navigation or approach aids introduced in the headset or speaker; and voice communication of flight crew members using the passenger address system, if installed.

The DGCA notification also stipulates that the cockpit voice recorder shall be capable of recording communication from the headphones and live-boom microphones of the pilot and co-pilot, area microphone and time reference pulse and the third and fourth crew members' headphones and microphones, if applicable, in different recording channels.

The CVR container should be painted in bright orange or bright yellow colour, have reflective tape affixed on its external surface and have an automatically activated underwater locating device.