hi!Have been scratching my head the whole day. I cannot find out how to switch between magnetic and true heading in the 737 instruments. I'm stuck at magnetic which seems to mess up the display of FMC track and Plane heading.Please help, driving me nuts....Best regardsJoachim

"I cannot find out how to switch between magnetic and true heading in the 737 instruments. I'm stuck at magnetic which seems to mess up the display of FMC track and Plane heading."You shouldn't need to switch to TRU heading unless you are flying in polar regions, Joachim (where the magnetic variation gets a little crazy). PMDG always shows "Magnetic".I think you're simply confusing heading with track(?). I think you'll find that most NG's use a "TRACK UP" Display as shown in PMDG(The track is fixed at the 12 o'clock position, but the heading varies according to wind).Cheers.Ian.P.S. Actually all navigation is based on TRUE on the NG, but the true values are converted into magnetic values, automatically, in non polar regions, for display purposes. All modern aircraft with IRS's or ADIRU's function this way. Other than the whiskey compass, there are no magnetic field sensors on the NG.