At what N2 rate is the start indicated by a green mark?

The green mark indicating the start on the N2 gauge shows that the engine has reached a critical speed necessary for the starting process to be considered successful. In the context of the CRJ 200, the N2 rate at which this green mark appears is 20%. This is an important milestone and signifies that the engine is achieving the required speed for ignition and subsequent combustion processes to begin.

Understanding this rate is crucial for pilots, as it helps them assess engine performance during the starting phase and ensures that they follow the correct procedures for a safe and efficient start. The appearance of the green mark at 20% also acts as a visual cue for pilots, indicating that whatever processes are integrated with N2 at this stage are progressing as designed.