In aviation, what does 'square the turn' mean?

The term 'square the turn' specifically refers to adjusting the bank angle during a turn to achieve a steady radius of the turn while maintaining altitude. This means that a pilot has to manage lift and centrifugal force to ensure that the aircraft does not climb or descend unintentionally while changing direction. Properly squaring the turn involves ensuring that the aircraft maintains a consistent speed and altitude throughout the maneuver, which is essential for safety and efficiency during flight operations.

In contrast, maintaining a straight flight path or descending at a constant rate does not involve any turning and thus does not relate to the concept of 'squaring the turn.' Increasing speed while turning may impact the dynamics of the turn but doesn't address the need for maintaining a constant radius and altitude during the maneuver. Therefore, the correct choice is about adjusting the bank angle appropriately to ensure those vital parameters remain stable.