What happens during a 90-degree turn with regard to bank angle readings?

During a 90-degree turn, the bank angle readings typically under-read due to the dynamics of how aircraft attitude indicators work. When making a turn, the aircraft's orientation and the gravitational forces acting on it affect the readings of the gyroscopic instruments.

In a standard turn, pilots aim for a specific bank angle to achieve the necessary rate of turn. However, as the aircraft enters a steep bank during a 90-degree turn, the centrifugal force acting outward can lead to an under-reading on the bank indicator. This discrepancy occurs because the indicators may not fully reflect the increase in actual bank angle that corresponds to achieving the desired turn performance.

This is particularly relevant in scenarios where the aircraft approaches a higher angle of bank, as the indicators may lag in updating to the actual aircraft position due to limitation in their design and sensor feedback. Understanding this characteristic of bank readings is crucial for pilots to maintain effective control and to execute turns accurately.