I find it incredible, too.  As UnoriginalGuy says, lab tests don&#x27;t always tell you what&#x27;s going wrong in the field.  But the fact that they don&#x27;t know what&#x27;s happening (if that&#x27;s true at all, some other posts have called the whole article into question) is still the designers&#x27; fault.  With modern hardware, the <i>most</i> important thing -- the thing you start building on Day #1 of the project -- is built-in diagnostics.<p>In the case of something like the 737 rudder problem, those planes were designed 40 years ago, in an era when it wasn&#x27;t practical to record every bit of operating data in real time, or add cheap, lightweight sensors to everything in sight.  That&#x27;s not true anymore.  Whether they&#x27;re building a drone, a fighter plane, a spacecraft, or even a modern passenger car, there is no excuse for requiring people to stand around some wreckage scratching their heads.  The onboard controllers should be able to tell them exactly what went wrong.  If they can&#x27;t, then <i>that&#x27;s</i> the problem to be solved first.