Is there a certain minimum temperature we need to turn on pitot heat on light trainers (eg DA40NG)?
In the AFM and checklist documents for the DA40NG, information is given that it should only be turned on when you enter unconditional icing conditions. What I'm wondering is, is there a certain minimum temperature value? For example, we are not in cloud conditions, the weather is sunny and there is no weather phenomenon, but the air temperature is low. For example, is the degree value we need to turn on the pitot heat 10°C, 5°C or 3°C? When it is 0°C, I think it is necessary to open it because it is already freezing.