Learn what an aircraft aileron is, how it creates roll, why adverse yaw occurs, and what reduces aileron effectiveness in flight and simulators.
An aircraft aileron is a hinged flight-control surface near the outer trailing edge of each wing. The two usually move in opposite directions: one rises while the other lowers, changing lift on each wing. That lift difference rolls the aircraft left or right around its longitudinal axis.
In our Aviation and Real-World Flying coverage, the key distinction is that ailerons control roll; the elevator controls pitch and the rudder controls yaw. Our guide to how the aircraft's control surfaces work together explains the wider system.
How does an aileron make an aircraft roll?
Ailerons produce a rolling moment by creating unequal aerodynamic forces on the left and right wings.
- The pilot commands roll. Moving the control stick sideways or turning the control wheel sends a roll command. This may pass through cables, pushrods, hydraulic actuators or a fly-by-wire system; our explanation of how a yoke operates the flight controls covers the cockpit input in more detail.
- The ailerons move in opposite directions. For a left roll, the left aileron normally rises and the right aileron lowers. A right roll reverses those movements.
- Wing lift becomes unequal. In normal, unstalled airflow, the raised aileron reduces local wing camber and lift. The lowered aileron increases local camber and lift.
- The aircraft rolls. The wing producing less lift descends while the opposite wing rises, rotating the aircraft around its nose-to-tail longitudinal axis.
An aileron commands a roll rate, not a fixed bank angle. As the desired bank approaches, the pilot reduces or briefly reverses the input to stop the roll, then keeps the controls close to neutral with small corrections.
Do ailerons turn the aircraft or only bank it?
Ailerons primarily bank the aircraft; the bank then causes the flight path to curve.
When the wings tilt, the total lift vector tilts with them. Its horizontal component pulls the aircraft into the turn, while the pilot may need to increase lift to maintain altitude. Rudder keeps the nose aligned with the curved flight path rather than creating the bank on its own.
This is why a properly flown turn uses coordinated aileron, rudder and elevator inputs. Our practical explanation of Cessna 172 controls shows how that coordination works in a familiar light aircraft.
Why do ailerons cause adverse yaw?
Adverse yaw occurs because the wing with the lowered aileron usually gains more drag as well as more lift, initially yawing the nose opposite the commanded roll.
During a left roll, for example, the right aileron moves down. The right wing's additional drag can pull the nose to the right even though the aircraft is banking left. The pilot counters this with coordinated left rudder, while some aircraft automate part of the correction.
| Roll-control design | How it works | Main purpose |
|---|---|---|
| Differential ailerons | The upward-moving aileron travels farther than the downward-moving one. | Reduces the drag imbalance and adverse yaw. |
| Frise ailerons | The nose of the raised aileron projects below the wing and adds drag on that side. | Helps balance yaw while retaining conventional roll control. |
| Roll spoilers | A spoiler rises on the descending-wing side to reduce lift and add drag. | Assists the ailerons, particularly on larger aircraft. |
| Flaperons | The same surfaces provide both flap and aileron functions. | Combines roll control with lift augmentation. |
Large transport aircraft may also have separate inboard and outboard ailerons. The outboard surfaces can be restricted at high speed to avoid excessive wing twisting and control loads.
Aileron effectiveness at low and high speeds
Aileron authority depends mainly on airflow over the surface, not simply the aircraft's groundspeed.
- Low airspeed: Reduced dynamic pressure makes the controls feel less effective, so greater deflection may be required.
- Separated or stalled airflow: An aileron can become weak or behave unpredictably when airflow separates from the wing.
- High airspeed: Small movements can produce substantial forces. Some aircraft limit aileron travel or change which roll-control surfaces operate.
- Local airflow: Propeller slipstream may keep part of a control surface effective even when the aircraft is moving slowly, but this varies greatly by design.
A mistake we see often in simulator flying is using full aileron as the automatic response to a wing dropping near the stall. Lowering the aileron on the stalled wing can increase its local camber and deepen the stall, encouraging autorotation. Recovery depends on the aircraft and its approved procedure, but reducing angle of attack takes priority over trying to force the wings level with aileron.
During crosswind take-offs and landings, aileron into wind helps prevent the upwind wing from lifting. The required input changes with airflow, so pilots adjust it throughout the ground roll rather than holding an arbitrary fixed deflection.
Why are ailerons not working correctly in a flight simulator?
Incorrect simulator aileron behaviour is most often caused by a reversed, duplicated or poorly calibrated roll assignment.
- Check the visible movement. A left roll command should normally raise the left aileron and lower the right one. Confirm this from a suitable cockpit or external view.
- Remove duplicate bindings. Assign the yoke or joystick to a single analogue roll axis and clear unintended roll commands from gamepads, keyboards and other controllers. MSFS users can compare their setup with the standard MSFS 2024 keyboard commands.
- Correct the axis direction. Use the reverse-axis option only when physical left input produces right roll. Sensitivity adjustments will not repair a reversed control.
- Calibrate drift and dead zones. A small unwanted input can make one aileron appear offset or cause a persistent roll.
- Check the aircraft state. Control locks, hydraulic failures, damage settings, autopilot operation and assistance features can limit or override the expected response.
- Test with adequate airflow. Correctly animated ailerons will not roll a stationary aircraft, and their authority will be weak close to the stall.
If the surfaces move correctly but the aircraft rolls the wrong way, test another aircraft with the same controller profile. Correct behaviour there points to an aircraft-specific flight model, systems state or add-on problem rather than the hardware assignment.