What is the maximum difference allowed for N2 at ground idle power?

The maximum difference allowed for N2 at ground idle power is a 2% split. This limitation is crucial for maintaining proper engine performance and ensuring that both engines are operating within acceptable parameters. A 2% split signifies that there can be a slight variation in the rotational speed of the two engines while still being within the operational limits designed to prevent potential mechanical stresses or imbalances. Exceeding this limit could lead to handling difficulties or excessive wear on the engines, which is why it is set to 2%. Understanding this limitation is essential for pilots and maintenance personnel to ensure safe and efficient operation during ground handling and takeoff preparations.