In ET, what bank angle is permissible during stable turns?

In the context of stable turns in formation flying, a bank angle of 30 to 60 degrees is generally permissible. This range allows for effective maneuverability while maintaining control and stability during the turn. A bank angle within this range strikes a balance between achieving the desired rate of turn and ensuring that the aircraft remains within a safe operational envelope, minimizing the risk of airflow issues that could lead to loss of control or formation integrity.

Using more than 60 degrees of bank could lead to increased g-forces and potential aerodynamic issues, which could be detrimental in formation flying where visually maintaining position relative to other aircraft is crucial. Conversely, bank angles of less than 30 degrees may not provide sufficient turning performance for the desired flight path in formation, making it less effective for maintaining position relative to the lead aircraft.

Hence, a bank angle of 30 to 60 degrees is optimal for stable turns in formation flying, allowing pilots to maintain both situational awareness and formation discipline.