Some aircrafts in FSX, both default and add-on (such as T210), will turn on Wing Leveler automatically when Altitude Hold is activated, meaning that manual control of the aileron is also disabled.

To regain the control of it, one can press Ctrl-V on the keyboard to disable (or enable) the function.

Better still, one can modify the aircraft.cfg files of such aircrafts, and add the following command lines under the [autopilot] section, so that Wing Leveler function could be independent from Altitude Hold permanently.

[autopilot]
default_bank_mode=0
default_pitch_mode=0

Assigning “1” to both values will reactivate the associated Wing Leveler function with Altitude Holder under auto-pilot mode.