Perhaps not. But they're probably running a computer model of the jet (and its systems) under various simulated scenarios. They're also probably building some

Perhaps not. But they're probably running a computer model of the jet (and its systems) under various simulated scenarios. They're also probably building some full-scale mock-ups to test in wind tunnels. And they also have test pilots to fly things which sometimes never make it into wide scale production. So, I'd argue that there is some iteration going on there.