Did some flying years ago. Anytime we were flying into nasty weather, and flight restrictions were imposed, we always had to desiginate an alternate airport on our flight plan. With this commuter carrying 50,000 pounds of fuel, why when severe icing conditions were encountered, didn't the pilot make a 180 degree turn and head for the alternate airport? This would be the prudent thing to do with passengers aboard. Surely they still use the alternate airport system today? If it was rime ice he was in trouble fast!