What indicates that SLD icing conditions exist during flight?

The indication of SLD (Supercooled Large Droplet) icing conditions during flight is characterized by the presence of ice accretion on side windows. This phenomenon occurs when larger droplets of supercooled water collide with surfaces of the aircraft, resulting in ice formation that can significantly affect performance and safety. Monitoring for ice on side windows serves as an important external indicator that SLD conditions are present, which necessitates the use of anti-ice systems and a careful assessment of the flight path to ensure safe operations.

While a temperature below 5°C could suggest potential for icing, it is not exclusively indicative of SLD conditions, as icing can occur even below freezing. Ice on the wings is a sign of icing but does not specifically indicate SLD; other types of icing can also create ice on the wings without the presence of SLD. Low visibility conditions can arise from various factors, including precipitation and fog, but they do not directly correlate to the presence of SLD icing. Therefore, ice accretion on side windows is the best indicator of SLD icing conditions.