EVEN USING THE BEST COMPUTERS, garbage in still produces garbage out.

“The computer models used to determine whether it was safe for airlines to fly through the ash resulting from the eruption of the Eyjafjallajökull volcano in southern Iceland were flawed ... and ‘based on incomplete science and limited data, according to European officials. As a result, they may have over-stated the risks to the public, needlessly grounding flights and damaging businesses.’ "