How many ice detectors must be operational for the A/I system to work in auto mode?

The Automatic Ice Protection (A/I) system of the Embraer Regional Jet requires only one operational ice detector for the system to function in auto mode. The ice detectors are critical for sensing ice formation on the aircraft's surfaces. When at least one detector senses ice, it will automatically activate the A/I system. This setup ensures that the aircraft can adequately respond to potential icing conditions while maintaining efficient operation.

The selection of just one operational detector indicates a redundancy strategy, allowing the system to remain functional even if one detector fails or is not operational. This design is intended to enhance safety and reliability during flight but minimizes the need for multiple detectors to be functional for the system to engage automatically.