Why does the rudder-centering key not work in FSX?

In FSX and FSX: Steam Edition, Num Pad 5 centres keyboard-applied aileron and rudder input only when it is assigned to “Center Ailerons and Rudder” and the numeric keypad is acting as flight controls. Num Lock, a changed binding, rudder trim or a continuously active joystick or pedal axis can make the key appear ineffective.

How do I get Num Pad 5 to centre the rudder?

Work through these checks in order; Num Lock and competing hardware axes account for most cases.

1. Turn Num Lock off. FSX normally uses the numeric keypad as a flight-control cluster in this state. Press Num Pad 5, not the 5 above the letter keys. Our complete FSX keyboard-command chart confirms the default centring command.
2. Check the active assignment. Open FSX's Controls settings and inspect the Buttons/Keys assignments. Num Pad 5 should be bound to Center Ailerons and Rudder, not a rudder-trim centring command. Remove conflicting assignments and restore the default if necessary; our instructions for verifying and repairing FSX key bindings cover the assignment process.
3. Account for compact keyboards. A laptop's embedded keypad or an Fn-key combination may not send the same input as a dedicated Num Pad 5. Assign Center Ailerons and Rudder to an unused, unambiguous key and test again.
4. Return focus to the simulator. Close any open assignment window, menu or add-on input box, then click the main FSX view before pressing the key. Another window with keyboard focus can consume the keystroke.
5. Test without controller input. Temporarily disable controller input, or disconnect the joystick and pedals before starting FSX. If Num Pad 5 then works, an analogue rudder axis is immediately replacing the centred value. Check for duplicate rudder assignments, calibration errors and insufficient null zone; these rudder-axis and pedal troubleshooting steps address those faults.
6. Try a default FSX aircraft. If the command works there but not in one add-on, the add-on is probably intercepting standard control events or using custom flight-control logic. Use that aircraft's own control configuration rather than repeatedly changing the global FSX binding.

What does the FSX rudder-centering key actually centre?

Num Pad 5 sends a combined command that returns the commanded aileron and rudder positions to neutral. It is a one-time control event, not a lock that holds the rudder at the centre against subsequent inputs.

It does not cancel rudder trim, restore the aircraft's heading, stop an existing yaw instantly or remove wind and engine effects. A common mistake we see is binding rudder-trim centring instead of Center Ailerons and Rudder; the two commands solve different problems.

Why does the rudder centre and then move again?

A rudder that snaps to neutral and immediately moves back is usually being driven by an analogue axis. FSX reads a pedal or twist-grip position continuously, so that fresh axis value overrides the one-time keyboard command on the next updates.

• If you intend to fly with pedals, keep the rudder axis assigned to the pedals only, recalibrate them and add a small null zone if the centre signal fluctuates.
• If you intend to use the keyboard, remove rudder-axis assignments from connected yokes, joysticks, throttles and game controllers.
• If Auto-rudder is enabled, switch it off temporarily while testing. It can introduce rudder input in response to aileron movement.
• If only one add-on is affected, check for its own yaw-damper, tiller or custom rudder controls.

Why does the aircraft still yaw with the rudder centred?

If the rudder surface returns to neutral but the aircraft keeps turning, the centring command has worked. Existing yaw inertia, a crosswind, propeller effects, asymmetric thrust, an engine failure, differential braking or ground weathervaning can continue moving the nose.

Rudder trim is another separate input and is not reset by plain Num Pad 5. Centre the trim with its own assignment and verify its position; our explanation of FSX trim controls and centring commands shows how trim differs from direct rudder input. Visual trim and control-surface animation can vary between aircraft, so judge the result using both the aircraft's indications and its behaviour.