From SLF
As a matter of interest, is it the case that cabin crew observations do not play a formal role in the procedures pilots use to diagnose problems like this?
I mean, if one of them got on the phone and mentioned that an engine was missing, or that there was burning fuel on the ground underneath an obviously broken engine, presumably the pilots would take them seriously, no matter what the official procedure said...
In the absence of a view from the cockpit and video displays of the wing, a pair of trained eyes down the back of the aircraft could be a useful thing.
So have I touched on the answer to my question - training (and the cost of it)? But for basic things like fire or absence you don't really need much training.
I wouldn't be surprised if retro fitting a video system was also much more expensive than one might casually think. However for new designs it would surely be a piece of cake. Or are they so keen to carry over pilot type ratings that they are adding nothing new like this at all? That would be a pity...