I wondered what the XXXs are. The manual explains these are internally generated by PF3.
They indicate points where you cross control center boundaries.
In the SIDs/STARS page, I designated RBV as the beginning of the STAR.
...
Once over RBV I'm told to "navigate at pilot's discretion (believing this means to the STAR)". Then, at least 100nm before my NGX FMC indicated TOD, I'm told to descend to descend to 16000ft. Ok, a little odd, but I do it. Then silence. Then as I navigate at 16000ft per FMC LNAV on the STAR route, the controller says that I'm 23 miles off the airway.
No logs for this one, so no idea what happened here.
There are only "resume own navigation" and "cleared to final for (something) at pilot's discretion", not sure which one you got here.
But as other posts here have indicated: It seems a little odd that your STAR starts more than 150nm from the destination airport.
The next time I try by not designating any STAR entry point in the hopes that ATC might guide me. Nope. Same thing. The only difference is that when I reach RBV there is no clearance for the "Sierra Tango" approach (generic for the STAR). Instead I hear nothing until being instructed to descend to 16000ft for the next incarnation of likely fuel exhaustion.
All ATC calls the log from "resume own navigation" to "Check position":
11:03:33 PM: 'Delta 4 resume own navigation '
11:03:41 PM: 'Roger resume own navigation Delta 4 '
11:04:01 PM: 'Delta 4 Climb to Flight Level 270 '
11:04:07 PM: 'Out of 6 thousand 5 hundred for Flight Level 270 Delta 4 '
11:04:37 PM: 'Delta 4 Contact NEW YORK CENTER on 134.65 '
11:04:43 PM: '134.65 Delta 4 '
11:04:52 PM: 'NEW YORK CENTER Delta 4 is with you, out of 9 thousand for Flight Level 270 IFR '
11:05:01 PM: 'Delta 4 Radar contact Altimeter is 3034 '
11:05:34 PM: 'Delta 4 Reduce speed to 250 '
11:05:38 PM: 'Reduce speed to 250 Delta 4 '
11:06:03 PM: 'Delta 4 Climb to Flight Level 270 '
11:06:10 PM: 'Out of 8 thousand 5 hundred for Flight Level 270 Delta 4 '
11:09:31 PM: 'Delta 4 Contact WASHINGTON CENTER on 134.55 '
11:09:37 PM: '134.55 Delta 4 Good day '
11:09:45 PM: 'WASHINGTON CENTER Delta 4 Out of 16 thousand 5 hundred for Flight Level 270 IFR '
11:09:56 PM: 'Delta 4 Altimeter is 3034 '
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At this point you were still at 15665ft, i.e. below the transition altitude. Something strange for us europeans
11:10:32 PM: 'Delta 4 Reduce speed to 310 '
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At this point you reached RBV, so PF3 prepared you give you descent instructions to the next waypoint XXX (16000ft) by slowing you down, but you did not reach neither your cruise altitude (32000ft) nor cleared flight level (FL270) yet, so it waited.
11:10:37 PM: '310 Delta 4 '
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At 11:15:21 you reached FL27, so PF3 could clear you for the next altitude at XXX:
11:15:26 PM: 'Delta 4 Descend and maintain 16 thousand Altimeter is 3037 '
11:15:34 PM: 'Out of Flight Level 270 for 16 thousand on 3037 Delta 4 '
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Now the problem is, PF3 expects you to navigate to your destination via XXX, the last waypoint before the destination airport.
But you should not need to do this, because you don't know where XXX really is (spoiler: on the line between RBV and the destination airport).
Dave, I suggest that PF3 should not create XXX waypoints between the last user waypoint and the destination, even if they should have been there. Optionally warn the user about the last waypoint being too far away from the destination.11:34:28 PM: 'Delta 4 Check position. We show you to be about 33 miles off the airway '
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At this point you have already passed XXX, but did not hit it. Asking for vectors or requesting direct to your destination might have helped, but I'm not even sure if they would be allowed at this point of the flight.
The best thing to do would be to make a better flight plan.
A workaround for this flight plan that Dave could implement is highlighted above.
I hope this analysis clarifies the reason for the disaster