Apologies if this has already been raised, but... is there any practical reason why manufacturers don't fit EPIRB devices to airliners ? I imagine it wouldn't be too difficult to engineer an impact-triggered release system that, in the event of a mid-air explosion or impact with water, would release a floating radio locator beacon (epirb). The cost of these devices are pennies in the grand scheme of things and would have been invaluable in this case, as well as AF447.
Does anyone know ?