Definition
The tendency of an airplane in a steep turn to continue rolling into a steeper bank without further control input by the pilot. It occurs because, in a turn, the outer wing travels along a larger radius than the inner wing and therefore moves faster through the air, producing more lift on the outer wing and rolling the airplane further into the bank.
Plain English
When you're already in a steep turn, the airplane wants to keep rolling into an even steeper turn on its own. You have to actively hold the bank where you want it, or even use opposite aileron, to stop it from getting steeper.
Context Anchor
Encountered during steep turn training, especially when learning to hold a constant bank angle without letting the turn tighten.
Derivation
"Over" meaning beyond what is intended, plus "banking," the act of rolling the airplane into a turn. The name describes exactly what happens: the airplane banks more than the pilot is asking it to.
Why Pilots Care
Unchecked, the increasing bank causes altitude loss, higher load factor, and can lead to an unintentional steep spiral.
Grounding Statement
Picture a steep left turn: the right wing is traveling around a larger circle than the left wing, so it moves a little faster and can make the airplane want to roll farther left.
Intuition Check
Do not read “tendency” as something the pilot is choosing to do. Here it means a natural behavior of the airplane that the pilot must recognize and control.
Example Sentence 1
As the bank passed 45 degrees, she felt the overbanking tendency and applied a small amount of opposite aileron to hold the bank steady.
Example Sentence 2
Recognizing the overbanking tendency early allowed the student to maintain constant altitude throughout the steep turn.