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All modern commercial airliners have a CVR (Cockpit Voice Recorder) on-board to record what the pilots are saying during the duration for a flight. I feel that the location of the microphones is important because they should be in a place that can easily pick up the cockpit conversations but should also be discreet enough to avoid accidental damage or even intentional sabotage by hijackers/suicidal pilots.

So where are the recording devices or microphones located in the cockpit for this?

Moreover:

  • Is there more than one microphone in the cockpit to provide stereo sound?
  • If so, do investigators listen to the recording from each microphone?
  • Are there any pictures of these microphones in the cockpit?
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    $\begingroup$ You could just switch off / trip the CVR if you wanted to sabotage the CVR. The flight investigators would probably work out you did, however. (See en.wikipedia.org/wiki/…) $\endgroup$ – Hugh May 27 '14 at 23:12
  • $\begingroup$ I am well aware of SilkAir 185, but thanks for sharing anyway :) $\endgroup$ – shortstheory May 28 '14 at 12:36
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The headsets worn by the pilots have a microphone arm. These audio channels are split and routed to the black box.

Additionally, there is at least one microphone embedded in the cockpit, usually overhead.

The black box can support recording of up to 4 audio channels, so each channel can be examined separately.

Since the headsets and overhead microphone are inside the cockpit, stereo audio is available.

Can't find any pictures for you, sorry!

Seethis sources:

Avstop

FAA (pdf)

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  • $\begingroup$ i don't know of any headset microphone that records in stereo; typically there are only two wires going out to the mic (and if there happen to be three, it's going to be an XLR configuration for noise reduction). you could certainly create a stereo signal from a single microphone, but that would be a huge waste of a whole channel on the cvr. stereo audio is only "available" if you do a little geospatial post-processing on the recorded signals, taking into account the locations of the microphones. $\endgroup$ – Erich Apr 2 '15 at 23:50
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Each of the three crew gets its own array of mics including the hand mic, boom mic, mask mic, his speaker and headphones (the microphone he uses for radio communication and what he hears from the radio). The third crew member's channel may be connected to the PA.

The fourth required channel is for the cockpit area mic which records general sounds and alerts.

Source: NTSB

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The Cockpit Area Microphone (CAM) can be in a variety of places due to different cockpit designs. Generally, it is supposed to be installed in the best position for recording voice communications.

On a Boeing 777, it is on the overhead panel next to the passenger seat belt sign switch:

B777 overhead
Image credit: Craig Murray / Airliners.net

On an Airbus A318/A319/A320/A321, it is in between the windscreen and the overhead panel, just below the exterior lights switches:

A320 overhead
Image credit: Niksa Radicevic / Airliners.net

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  • $\begingroup$ the 777 sure has a funky looking microphone! +1 for the nice pictures :) $\endgroup$ – shortstheory Apr 2 '15 at 14:31

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