After completing a flight plan in the FMC I inadvertently swept my hand across the left-hand end of my keyboard. I witnessed the flight plan swivel clockwise through 18 degrees on the HSI which had the effect of causing my runway takeoff heading to end up at 330 degrees instead of 312.I noticed that flight plans prepared for the 747 were affected in exactly the same way.I removed and reinstalled both the MD-11 and the 747 but the disorientation remains.None of my other aircraft addons are affected.Clearly some key or keys have the effect of changing the orientation but I have no idea which.Has anybody had a similar experience and do they know how to correct it?Colin

I think you'd get a better and faster answer by posting this in the PMDG forum.