how to use rudder trim of boeing 737

[chinadragonboy]

could some one explain to me about how to use rudder trim of boeing 737 when my aircraft get closer to runway . if use heading ap on , when i adjust a little , still can not make my aircraft in line with runway . this is very hard for me . well , please advise if AP is on , still can use rudder trim ? or how to use it . shift or ctrl ? please help me . thanks . paul

[liran_bar]

Hey man!
when the approach hold is on and the autopilot is activated you shouldn't touch any thing.... it does it alone.....
besides.... rudder cannot be activated at once, especialy not on decends when your speed is greater than the power the engine ativates... because when you apply the rudder you do change the engines' power direction but it's still much weaker than the orantation power of the plane (I am not sure about the spelling, but it's that law in physics that says that every item with a mass will always want to keep his current motion...in this case- forward)

so, when you rudder, especially at decends give it some time before you expect the effects....

Liran Bar, Israel