Hi guys, I currently have little problem with the NGX: I can't find that HDG/TRK button to switch between these two modes. Can someone tell we where this button is actually located?

Hi, please clarify: do you want to switch the ND from displaying heading up to track up? That can be changed in the display options section of the MCDU.If you mean HDG/TRK modes for the autopilot, that button is located on the flight-deck of the nearest Airbus. Not an option on the 737 as far as I'm aware - only heading select.

The first one.EDIT: The right ND looks now like it isn't fed by the right IRS. The captains side works perfectly. It seems like I've lost the FO's IRS but I don't have any faillures active. Very strange but as long as we're flying, everything is all right.