<<One has to wonder about the design as well. Is there not some sort of signal in the cockpit to warn them that they have forgotten to put the gear down?>>
Of course there is, and it doesn't make any difference in incidents like this one. Once the normal sequence of things in an approach to landing has been interrupted by something, a minor distraction for example, then all the warning horns and lights don't seem to get through to the crew. I could describe a typical example of this sort of thing (didn't involve me) that cost a friend about 30 grand but I won't bore you. RLE