ARCH Air Medical Service, Inc. is an Emergency Medical Service (EMS) that provides critical care air ambulance service in Missouri, Illinois and the surrounding regions. Air ambulance programs (also known as Medevac) offer transport by helicopter (rotor-wing or sling-wing) or fixed-wing aircraft. ARCH Air was the twelfth program in the nation to offer such services when it began operating in March 1979. Transporting approximately 4,200 patients per year by rotorwing, ARCH aircraft are staffed by a pilot, nurse and paramedic. Flights are 80% inter-facility (hospital to hospital) and 20% scene.