What does "bank angle" indicate in an aircraft?

The term "bank angle" specifically refers to the angle formed between the horizontal plane and the aircraft's wings during flight. This angle is critical in defining how the aircraft is oriented relative to the ground. A positive bank angle indicates that one wing is lower than the other, facilitating the aircraft's ability to turn. Understanding bank angle is essential for pilots, as it directly affects the aircraft’s lift and drag, and consequently its performance in maneuvering and maintaining controlled flight.

In terms of flight dynamics, a proper bank angle is required to safely negotiate turns, enabling pilots to manage their speed and altitude effectively while maintaining aircraft control.