To maintain a standard rate turn as airspeed increases, what must happen to the bank angle?

As airspeed increases during a standard rate turn, the bank angle must increase in order to maintain that turn rate. This is due to the relationship between bank angle and the load factor acting on the aircraft. In a turn, the lift must not only counteract the weight of the aircraft but also provide additional lift to facilitate the turn. When airspeed increases, the horizontal component of lift becomes larger, requiring a greater angle of bank to maintain a constant turn radius and rate of turn.

In essence, increasing the bank angle allows the wings to generate more lift in response to the increased load and maintain the desired standard rate turn. Pilots must be aware of this dynamic to ensure that they manage their turns properly, especially in varying airspeeds.