PSA Airlines Canadair Regional Jet Systems (PSA-CRJ) Practice Exam

When are Ice Detector probes activated for heating?

1. Immediately upon aircraft power-up

2. When icing is detected and vibration decreases

3. During taxi operations

4. Only when temperatures drop below freezing

The correct answer is: When icing is detected and vibration decreases

The correct answer is that Ice Detector probes are activated for heating when icing is detected and vibration decreases. Ice Detector probes are designed to monitor conditions for ice formation. When ice begins to accumulate, the system detects a change in vibration and subsequently activates the heating elements in the probes to prevent further ice buildup. This reaction ensures that the probes remain functional and can continue to monitor for icing conditions effectively. The activation based on actual icing detection helps in optimizing system performance and preventing unnecessary heating when conditions are insufficient for ice formation. The other options do not accurately describe the operational behavior of the Ice Detector probes. For instance, activating the probes immediately upon aircraft power-up might lead to unnecessary heating which is not required unless there are specific icing conditions present. Similarly, activating during taxi operations or only when temperatures drop below freezing does not account for the potential for ice accumulation at temperatures above freezing and under certain environmental conditions, such as high humidity.