(Bloomberg) -- A system designed to help air-traffic controllers monitor vehicles and airplanes on the ground failed to alert personnel at LaGuardia Airport before an Air Canada Express jet collided with a fire truck late Sunday evening, killing the two pilots. An analysis found the system, known as ASDE-X, issued no alert to the two controllers in the tower due to “the close proximity of vehicles merging and unmerging near the runway,” US National Transportation Safety Board Chair Jennifer Homendy said dur ...