Today while landing at LIRF I was all set up for arrival on runway 16R (110.30/162). ILS frequency and heading in the PIC FMC agreed with charts but I was off by a heading of approx 35 to 40 degrees. My gyro drift is set to OFF. Any explanation ???Mark.

What Heading was in the NAV CRS selector?

162 deg.The extended runway on the MAP and the ILS where both "off". Certainly the MAP should show correctly regardless of the CRS heading.Mark.

check your latest installed sceneryturn it off, try again, if the problem is solved... throw away the scenery... had this aswell but for the entire world...was simply a magvar file somewhere in the scenery folder... a pitty

This is in FS2002 so no scenery has been added for since the last time I flew when everything was OK. I will try again tonight and test with PIC and another plane to see if this is still an issue.Mark.

Are you talking about the gyro drift in the flightsim realism settings that you have disabled? If you are not realigning you IRS after each flight you will get a drift, but if you are talking about the drift option in the courier options selection for PIC. Otherwise I don't know wha it could be.

Yes, I have diabled gyro drift in the realism settings....mostly because of the adverse affects this setting has on the PSS Dash 8. Anyway, tried it again last night and no problem, everything is back to normal...hopefully it stays that way.Mark.

>>This is in FS2002 so no scenery has been added for since the>last time I flew when everything was OK. Mark,I had exactly the same happen very recently. And Lenny is right, it's a scenery problem. To be more specific, I found out I had double AFCAD for Boston (yes, it was happening in and around Boston). In my case the deviation in heading was about 90 degrees.

Mark,You have installed a scenery which copied a AFCAD2 file to your FS2002 scenery folder. If you get AFCAD2 files ment for FS2004 into FS2002 this is the symptom. Check your scenery folders for AF2_*.bgl files.Hope it helps,