Definition
A small, deliberate aileron input held to keep the wings level when an aircraft has a tendency to roll one way on its own. It is not a turn; it is a steady, light pressure applied to counteract a rolling tendency caused by factors such as torque, propeller effects, fuel imbalance, or rigging.
Plain English
A tiny amount of bank you hold in to stop the airplane from slowly rolling on its own. Just enough pressure to keep the wings level — no turn results from it.
Context Anchor
Seen in instrument straight-and-level flight when small control pressures are used to keep the heading from wandering.
Derivation
The word ‘supporting’ comes from the Latin supportare, meaning ‘to carry’ or ‘to hold up.’ Here it carries the sense of holding the wings up against an unwanted rolling tendency — the bank input is supporting the level attitude, not creating a turn.
Why Pilots Care
Without recognizing the need for a supporting bank, a pilot may chase heading drift with rudder or over-correct, leading to unsteady flight on the gauges. Holding the right amount of supporting bank lets the aircraft fly straight with minimal effort, which is essential on instruments where small heading errors compound quickly.
Grounding Statement
On the instruments, a supporting bank may look like a barely noticeable tilt while the heading stays fixed.
Intuition Check
Supporting bank does not mean the airplane is turning normally. It means a small bank is being used to stop an unwanted turn and keep the heading steady.
Example Sentence 1
On the climb-out, the pilot held a slight supporting bank to the right to keep the wings level against the left-turning tendency of the propeller.
Example Sentence 2
During straight-and-level flight the supporting bank is wings level so the turn coordinator shows zero rate.