The AVOID system is a tactical awareness device for providing real-time imagery of hazards ahead of a jet aircraft. Information is supplied to the cockpit from two fast-sampling, imaging infrared cameras that are tuned to detect hazardous volcanic ash particles in the airspace up to 100 km ahead of the aircraft day or night. At normal flight cruising altitudes and speeds this will give a pilot-7 – 10 minutes warning of a potential dangerous encounter with an ash cloud. AVOID software is used to convert the image signal into ash concentrations, providing an indication of levels from less than 1 mg m-3 to over 50 mg m-3. When coupled with GPS and airspeed data, “ash dosages” can be quickly determined and displayed in real-time. The information can also be relayed back to air-traffic control centres or to other aircraft not equipped with the AVOID system.