FLC OF A CPR LTT JET ACFT INADVERTENTLY FAILED TO MAKE A DSCNT ALT RESTRICTION DUE TO A MISPROGRAMMED GNS (GLOBAL NAV SYS).

Narrative

WHILE ON THE METRO 3 ARR INTO MMU WE WERE TOLD BY ATC TO CROSS SWANN INTXN AT 16000 FT; WHICH WE MADE. WE WERE THEN TOLD TO CROSS SOMOTO INTXN AT 11000 FT. WE WERE USING THE VORS AND OUR GLOBAL NAV SYS AS BACKUP. JUST AS WE PASSED SOMOTO INTXN AT 14000 FT WE WERE TOLD BY ATC THAT WE HAD MISSED OUR XING RESTRICTION. THE GLOBAL NAV SYS WAS IN ERROR AND WAS TELLING US THAT WE HAD NOT YET REACHED SOMOTO INTXN. AFTER XCHKING WITH THE VORS AS SECOND IN COMMAND; I DID REALIZE THAT WE HAD MISSED OUR XING RESTRICTION. I IMMEDIATELY REPLIED TO ATC THAT WE WERE SORRY AND WE WOULD CHK OUT THE PROB. THE CTLR SAID 'HE COULD NOT MAKE THOSE KINDS OF MISTAKES AND FOR US TO CROSS YARDLEY VOR AT 8000 FT.' WE HAD NO TROUBLE MAKING THAT RESTRICTION. WE WERE THEN TOLD TO CONTACT NY APCH. AS PROFESSIONAL PLTS WE DO MAKE MISTAKES. WE IN NO WAY PURPOSELY INTENDED TO MISS THE XING RESTRICTION. THE FLT TERMINATED WITH NO OTHER PROBS WITH A SAFE PROFESSIONAL ILS INTO MMU; MORRISTOWN; NJ; OUR DEST. IN THE FUTURE WE WILL MONITOR THE GLOBAL NAV SYS MORE CLOSELY AND UPDATE THEM MORE OFTEN. WE ALSO DECIDED TO HAVE A SECOND COPY OF THE ARR SO THE SECOND IN COMMAND COULD MONITOR THE ARR BETTER. WE FEEL THAT THERE WAS NO CONFLICT WITH ANY OTHER ACFT. WE ALWAYS WORK WITH ATC AND REALIZE THE NEED AND IMPORTANCE FOR GOOD PROFESSIONAL CTLRS. SUPPLEMENTAL INFORMATION FROM ACN 242122: HOWEVER; IN THIS INSTANCE WE DID MAKE A MISTAKE. AFTER DISCUSSING THE INCIDENT AT THE COMPLETION OF OUR FLT IT BECAME OBVIOUS THAT BECAUSE WE DID NOT UPDATE THE POS OF THE GLOBAL NAV SYS ENRTE WE MISSED A XING RESTRICTION. IN THE FUTURE BOTH PLTS WILL HAVE A COPY OF THE APCH PLATES WHEN IN UNFAMILIAR AREAS. GLOBAL NAV SYS'S WILL BE UPDATED REGULARLY ENRTE AND XCHKING OF VORS AND GLOBAL NAV SYS POS WILL AGAIN BECOME A PART OF THE DAILY COCKPIT RESOURCE MGMNT.