>So how is this situation handled in 2-crew operations? What procedures do you follow to ensure that you know exactly what's going to happen when the aircraft turns towards that seemingly random point that you first heard of a few seconds ago?
The company requires that I have the enroute chart out. If I cannot find the fix as he speaks, I will reply, "standby, I'm looking for that one." If it's off our filed route, we'll bring that up at the end of the readback, and normally that gets him to rescind it (he thought we were going on a different route). Other times that's not the case, and we then verify the expected routing after that fix. That allows us to put the pieces of the puzzle together, verify it on the chart, the Map display, and the FMS, and then watch the jet navigate.
There was one problem recently in southeastern Iran SE of Kerman on UL124. The FIR boundary crossing fix into Karachi airspace had moved south about 15 nm, and it was not on any of the charts yet. Company notified us, and we found it in the chart NOTAMS. We backed up the manual Lat/Long entries with VOR radials to make sure we were spot on. It's uncomfortable, though, when the FMS does not like the route you input.