CVR question
One of the many frustrating and ironic twists in this baffling accident is that, if and when the CVR is finally found (and recovered), it will in all probability, just contain two hours of silence - because only the last two hours of cockpit audio is retained on the CVR. All preceding audio is over-written thus denying investigators arguably their best clues to this bizarre tragedy.
My question is this - How complete is that over-writing?
We all know that deleted data from a PC hard drive can still be read - if you know the right (maybe that should be 'wrong') people. We have already seen this demonstrated with regard to the Captain's flight sim. data.
Could this also be made easier by being over-written by continuous silence? Could there be recoverable 'soft' data under that pure white over-write? Or are there some subtle technical differences between delete, erase and over-write?