Hi guys,

Before start we control that the Rudder And Aileron trim is free and in Zero position but can anybody tell me when the maneuvre wheels in the pedestal is used?

 

Is it during normal operations or abnormal? Cant find the explanation of the use

 

Thanks

Michael Moe

In real life aircraft are never 100% symmetrical, each one is very slightly different so may require a small trim input to correct any roll and yaw asymmetry. In the sim this doesn't happen of course, so rudder and aileron trim are only really needed for abnormal situations.

 

Rudder trim would mainly be necessary if you had an engine failure, which creates a thrust asymmetry and so a yawing moment. This requires some rudder input to stop the aircraft spiralling. Rudder trim offsets the rudder's neutral (centre) position so the pilot only needs to make small pedal inputs. Once the rudder is trimmed there will probably be some roll asymmetry too, so aileron trim may also be necessary to help keep the wings level.

 

A small fuel imbalance can also be corrected with aileron trim. Large fuel imbalances should be corrected by using fuel crossfeed from the heavier wing.

Just an extra point to note, in real life the AP is not to be used with aileron trim and I have never used aileron trim in real life or during a sim check. Rudder trim is usually needed on most flights to center the control wheel in the cruise with balanced fuel and equal thrust. See the Cruise chapter of the FCTM for more info and techniques.

thanks will look it up

 

Michael Moe