Everything about Cockpit Voice Recorder totally explained
A
Cockpit Voice Recorder (CVR) is a
flight recorder used to record the audio environment in the flightdeck of an aircraft for the purpose of investigation of accidents and incidents. This is typically achieved by recording the signals of the microphones and earphones of the pilots headsets and of an area microphone in the roof of the cockpit. The current applicable
FAA TSO is C123b titled Cockpit Voice Recorder Equipment.
Where an aircraft is required to carry a CVR and utilises digital communications the CVR is required to record such communications with air traffic control unless this is recorded elsewhere. It is at present (2005) a requirement that the recording duration is a minimum of thirty minutes, but it's recommended that it should be two hours.
Overview
A standard CVR is capable of recording 4 channels of audio data for a period of 2 hours. The original requirement was for a CVR to record for 30 minutes, but this has been found to be insufficient in many cases, significant parts of the audio data needed for a subsequent investigation having occurred more than 30 minutes before the end of the recording.
The earliest CVRs used analog
wire recording, later replaced by analog
magnetic tape. Some of the tape units used two reels, with the tape automatically reversing at each end. The original was the
ARL Flight Memory Unit produced in
1957 by
David Warren and an instrument maker named
Tych Mirfield.
Other units used a single reel, with the tape spliced into a continuous loop, much as in an
8-track cartridge. The tape would circulate and old audio information would be overwritten every 30 minutes. Recovery of sound from magnetic tape often proves difficult if the recorder is recovered from water and its housing has been breached. Thus, the latest designs employ solid-state memory and use digital recording techniques, making them much more resistant to shock, vibration and moisture. With the reduced power requirements of solid-state recorders, it's now practical to incorporate a battery in the units, so that recording can continue until flight termination, even if the aircraft electrical system fails.
Like the
flight data recorder (FDR), the CVR is typically mounted in the
empennage of an airplane to maximize the likelihood of its survival in a crash.
Future devices
The
U.S. National Transportation Safety Board has asked for the installation of cockpit image recorders in large transport aircraft to provide information that would supplement existing CVR and FDR data in accident investigations. They also recommended image recorders be placed into smaller aircraft that are not required to have a CVR or FDR.
Related
The
U.S. National Transportation Safety Board has recommended that
railroad voice recorders be required in
locomotives.
Cultural references
The
Neue Deutsche Härte band
Rammstein's album
Reise, Reise is made to look like a CVR; it also includes a recording from a crash. The recording is from the last 1-2 minutes of the CVR of
Japan Airlines Flight 123, which crashed on August 12, 1985, killing 520 people; JAL123 is the deadliest single-aircraft disaster in history.
Members of made a theatrical presentation based on transcripts from CVR recordings.
A play called
Charlie Victor Romeo has a script consisting of almost verbatim cockpit voice recordings.
Survivor, a novel by Chuck Palahniuk, is about a cult member who dictates his life story to a flight recorder before the plane runs out of gas and crashes.
Further Information
Get more info on 'Cockpit Voice Recorder'.
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