Some very useful opinions thanks !!!
I still think that even a black and white camera would be useful. Looking at the 89 Manchester 737 fire - the crew's immediate response to the 'thud' as the engine exploded was that it was a tire break (of which there were no signs to the contuary).
It took 19 seconds after the engine had blown for the flight deck crew to become aware of the actual situation and when the warning lights did come on there was no indication that the fire was uncontained - a far more serious fault that had the flight crew been aware could have initated a different response.
A CCTV camera with a screen in the flight deck in this situation would have made the pilots much more aware of the situation at hand and therefore possibly better able to act on their training. Even if the image was completely white it would still give greater insight.
A similiar situation with the Kegworth 737 crash - I am not sure if the left engine would exibited any visual signs of failure but the right engine certainly wouldn't - a visual image of this may have given the pilots the opportunity to question the information that they were being given. Perhaps key in adverting the disaster.
Again not sure how the flight data recorder works - but I assume that it must be refreashed before each flight...
For me a visual image of the aircraft in these problem situations would be invaluable as surely it presents the pilots with the whole picture !!
Apart from the physical problems of the camera logistics. Would there be any SOP problems - questions over a visual image diverting the pilots attention ???