Learn what aileron trim does, when pilots should use it, how to set it correctly, and which rolling problems trim must never hide.
In aviation and real-world flying, aileron trim is a system that holds a small roll-control input so the pilot does not have to maintain sideways pressure on the yoke or stick. Use it only to relieve a persistent rolling force in steady flight, after checking configuration, balance and coordination—not for momentary bank corrections.
Aileron trim does not automatically keep the wings level. Direct aileron input produces an immediate roll response; trim removes the effort required to maintain a small, sustained correction. Our guide to how control surfaces and trim systems affect an aircraft covers the underlying aerodynamics.
How does aileron trim work?
Aileron trim creates a small control force or changes the neutral point of the lateral control system. The exact mechanism depends on the aircraft:
- Trim tab: A small movable surface on an aileron creates the hinge moment needed to hold the correction.
- Spring or bungee system: The trim control changes the centring force felt through the yoke or stick.
- Powered or electronic system: The flight-control system adjusts its commanded neutral position or force reference.
Not every aircraft has pilot-adjustable aileron trim. Many light aircraft provide elevator trim but use a fixed or ground-adjustable aileron tab instead. That tab is a maintenance adjustment and must not be bent or altered by the pilot.
Aileron trim controls roll, while rudder trim controls sustained yaw or pedal force. The distinction matters because an uncoordinated aircraft can appear to have a heavy wing even though the real problem is yaw; see our practical comparison of rudder and aileron trim.
When should you use aileron trim?
Use aileron trim when a correctly configured and coordinated aircraft requires continuous lateral pressure during a stable phase of flight.
| Situation | Use aileron trim? | Correct response |
|---|---|---|
| Persistent light wing in steady cruise or a prolonged stable climb | Yes | Check balance and coordination, then trim away the sustained control force. |
| Fuel or payload imbalance within permitted limits | With caution | Manage the imbalance using the approved procedure; use trim only for the residual force. |
| One-engine-inoperative flight | Only as specified | Establish the prescribed rudder input and bank angle first, then use available trim according to the aircraft checklist. |
| Gusts, turbulence or an ordinary turn | No | Use direct aileron input because the correction is temporary. |
| Crosswind during approach and landing | Normally no | Use the flight controls directly; the required input changes rapidly and must not remain after a go-around. |
| Sudden, severe or increasing roll tendency | No | Treat it as an abnormal condition and check for asymmetric flap, icing, damage, fuel imbalance or a control-system problem. |
| Take-off or landing configuration | Published setting only | Use the position specified by the aircraft documentation, commonly neutral, rather than carrying an improvised cruise correction. |
A steady crosswind at altitude does not by itself require permanent aileron trim. A correctly coordinated aircraft simply adopts a crab angle; gusts and wind shear require temporary control inputs instead.
How do you set aileron trim correctly?
Set aileron trim by holding the required attitude with the primary controls, then moving the trim in small increments until the sustained pressure disappears.
- Stabilise the aircraft. Let airspeed, power, configuration and flight path settle. Unless the approved procedure says otherwise, do not trim manually against an engaged autopilot.
- Identify the cause. Check fuel balance, payload, flap and gear indications, icing, yaw coordination and any asymmetric thrust.
- Hold the correction. Use the yoke or stick to maintain wings level or the required bank angle.
- Trim off the pressure. If you are holding right aileron to prevent a left roll, apply a small amount of right aileron trim and verify that the force decreases. Follow the aircraft's own trim labelling if it differs.
- Recheck after changes. Power, speed, flap, fuel balance and thrust changes can alter the required setting.
The working rule is fly first, then trim. Using trim to roll into a turn usually causes an overshoot and leaves an unwanted correction that must be removed afterwards.
Why does the aircraft still roll after trimming?
A continuing roll after trimming usually means the underlying cause has not been corrected or the trim command is not behaving as expected.
In a flight simulator, check for an off-centre joystick axis, inadequate dead zone, duplicate assignments, a second trim axis, assistance features, asymmetric fuel or payload, and uncoordinated yaw. Aileron trim should not be used to conceal faulty controller calibration; our MSFS and X-Plane trim assignment guide explains the difference between trim buttons and a continuous trim axis.
In an actual aircraft, a new or worsening heavy wing demands the applicable checklist rather than more trim. If the trim moves without a command, continues travelling or produces rapidly increasing force, treat it as a malfunction and use the documented procedure for recognising and recovering from runaway trim.