@wigyori: Good points, thanks. I see what you're saying about retail/industrial, and I wasn't quite suggesting that the airlines just pop down to the shops and buy a few GoPros off the shelf for each craft
But nonetheless the technology is getting better and cheaper all the time, and one would imagine that principle would apply on an industrial scale just as it does in the consumer market, even if the actual numbers are higher.
There's no technical reason why video recording equipment could not be fitted, and data recorded in a similar way to how it's done with the CVR.
The pilot unions have been against this for years though on the grounds of privacy.