FO; ONLY FLYING OFFICER ON DECK; MISREAD CLRNC; LATE INSERTING WAYPOINT; COURSE DEV FROM CLRNC.

Narrative

THE INS NAV UNITS WERE REPROGRAMMED TO INSERT THE COORDINATES FOR MERLY INTXN SO THAT WE COULD PROCEED DIRECT TO IT. SEVERAL MINS AFTER PROCEEDING DIRECT TO MERLY; THE CAPT LEFT THE COCKPIT TO ATTEND TO PHYSIOLOGICAL NEEDS. SHORTLY THEREAFTER; OUR FLT WAS HANDED OFF TO LONDON CTL. UPON MAKING INITIAL CONTACT; LONDON CTL HAD A REVISION TO OUR ROUTING. I COPIED THE CLRNC AS MERLY UR37 SAM DIRECT MID DIRECT CLN UR12 AMSTERDAM. LONDON CENTER ALSO INQUIRED AS TO WHETHER WE WOULD BE ABLE TO ACCEPT FL370 FOR TFC SEPARATION. I TOLD LONDON TO STAND BY WHILE WE CHKED ON WHETHER WE WOULD BE ABLE TO CLB TO FL370. AT THIS TIME; I WOULD ESTIMATE THAT WE WERE 120 NM TO THE W OF MERLY. THE INS UNITS WOULD REQUIRE REPROGRAMMING FOR THE REVISED ROUTING AFTER MERLY; BUT THERE WAS AT LEAST 12 MINS BEFORE WE WOULD GET TO MERLY. OUR PROCS CALL FOR INS WAYPOINT INSERTION TO BE DONE BY THE CAPT UNDER NORMAL CIRCUMSTANCES; AND I EXPECTED HIM BACK IN THE COCKPIT WELL BEFORE REACHING MERLY. THEREFORE; I DID NOT REPROGRAM THE INS UNITS (INSERT WAYPOINT COORDINATES) FOR THE ROUTING AFTER MERLY. AFTER CHKING ON THE FEASIBILITY OF CLBING TO FL370; I HAPPENED TO NOTICE THAT THERE WAS ANOTHER INTXN (NORLA) ON UR37 CLOSER TO THE POS. I ASKED LONDON CTL IF THEY HAD INTENDED US TO PROCEED DIRECT TO NORLA (INSTEAD OF MERLY). THE CTLR REPLIED YES AND GAVE OUR POS AS 12 NM SW OF NORLA. I IMMEDIATELY INSERTED THE COORDINATES FOR NORLA INTO THE INS UNITS AS WAYPOINT #3 (PREVIOUSLY MERLY). AFTER INSERTING THE COORDINATES; I SELECTED PRESENT POS DIRECT NORLA. UNFORTUNATELY; BEFORE I COULD PROGRAM THE WAYPOINTS FOR THE REVISED ROUTING; WE REACHED NORLA INTXN AND THE ACFT TOOK UP A COURSE TO THE NEXT WAYPOINT ON OUR PREVIOUS ROUTING BCN VOR. THE CTLR NOTICED OUR DEV FROM UR37 AND ISSUED A HDG OF 120 DEG TO REINTERCEPT THE AIRWAY. AT THIS TIME; THE CAPT REENTERED THE COCKPIT; AND THE INS UNITS WERE REPROGRAMMED FOR THE NEW ROUTING TO AMSTERDAM. VOR NAV WAS UTILIZED UNTIL REPROGRAMMING WAS COMPLETE.