What is the acceptable ITT rise during the engine anti-ice ground check indicative of?

The rise in Interstage Turbine Temperature (ITT) during the engine anti-ice ground check is a critical indicator of the engine's performance when the anti-ice system is activated. When the anti-ice system is functioning correctly, it allows for the prevention of ice formation on the engine components, which can impact performance.

A rise in ITT signifies that the engine is compensating for the additional load imposed by the anti-ice system working effectively. This indicates that the system is functioning properly and the engine is able to manage the increased thermal demands without negatively affecting performance.

In contrast, options relating to insufficient performance or possible engine failure would result in abnormal ITT readings and are not indicative of a properly functioning anti-ice system. The response would flag issues rather than affirming the effectiveness of the anti-ice system, aligning with what is expected in normal operational conditions when the anti-ice is engaged. As a result, observing an acceptable ITT rise during this check confirms that the engine anti-ice system is operating as designed.