An Air Canada Express regional jet collided with a Port Authority firetruck on a runway at LaGuardia Airport in New York late Sunday night, resulting in the closure of the major transportation hub.The Bombardier CRJ-900 aircraft, operated by Jazz Airlines, was arriving from Montreal with approximately 100 passengers on board when the incident occurred during heavy rain.Four firefighters from the Port Authority Police Department sustained critical injuries during the impact on Runway 4 and were transported for emergency medical treatment.The Federal Aviation Administration issued an immediate ground stop for
LaGuardia Airport while the National Transportation Safety Board begins an investigation into the crash.