What indicates SLD icing conditions?

The presence of ice accumulation on the side windows is a strong indicator of supercooled liquid water, which is primarily responsible for SLD (Supercooled Large Droplet) icing conditions. When flying through clouds or precipitation containing these supercooled droplets, ice can form on the aircraft's surfaces, including windows and wings, even at relatively warm temperatures where ice might not typically be expected. Monitoring the ice accumulation on windows can give pilots clear visual evidence that SLD icing is occurring, alerting them to potential hazards that could compromise aircraft performance and safety.

Other aspects, such as low temperature warnings, visibility reduction, and engine performance loss can be associated with icing conditions but do not specifically indicate SLD icing. Low temperature warnings might suggest cold conditions conducive to icing, but they are not exclusive to SLD scenarios. Visibility reduction could occur in various weather conditions unrelated to SLD, and engine performance loss may result from icing but is also influenced by many other factors. Therefore, the visual cue of ice accumulation on the windows is the most direct and immediate indicator of SLD icing.