Under what conditions are icing conditions defined for the ERJ 170/175?

Icing conditions for the ERJ 170/175 are defined specifically when both visible moisture is present and the aircraft is operating on contaminated surfaces. This definition is crucial for safe flight operations as icing can adversely affect the aircraft's performance, aerodynamics, and safety.

Visible moisture refers to any form of water that can be seen in the air, including rain, snow, sleet, or fog, which can lead to ice accumulation on the aircraft’s critical surfaces such as wings and control surfaces. Contaminated surfaces include runways or taxiways covered with ice, snow, or slush, which further increase the likelihood of ice formation on the aircraft during ground operations.

The combination of these two factors significantly heightens the risk of icing. Thus, pilots must remain vigilant and take appropriate precautions when both visible moisture and contaminated surfaces are present, making the definition comprehensive and the safest practice for determining icing conditions.