FLC OF AN MLG FAILED TO CHANGE COURSE AS ASSIGNED DURING HIGH ALT CRUISE UNTIL NOTICING THE ERROR 25 MI PAST THE VOR FIX.

Narrative

ENRTE FROM ORD TO BWI AT FL330 INBOUND TO DJB VOR CTR CLRED US 'AFTER DJB VOR DJB DIRECT MGW' (RATHER THAN OUR FLT PLAN RTE OF V162 WHICH WOULD HAVE TAKEN US VIA AIR ENRTE TO MGW). APCHING DJB VOR I ALLOWED MYSELF TO BECOME DISTRACTED IN ASSISTING THE CAPT WITH SENDING AN ENG TREND MONITORING RPT VIA THE ACARS. WHEN I NEXT LOOKED BACK AT MY FLT INSTS WE WERE 25 DME BEYOND DJB VOR STILL ON OUR HDG THAT HAD TAKEN US TO DJB HAVING MISSED MAKING THE TURN DIRECT TO MGW OVER DJB VOR. COURSE CORRECTION WAS INITIATED. I BELIEVE THE PRIMARY CAUSE OF THIS EVENT WAS COMPLACENCY INSPIRED BY THE 'COMFORT' OF BEING IN THE CRUISE SEGMENT OF THE FLT. SECONDARY CAUSES WHERE A SHORT LAYOVER/'MINIMUM REST' THE NIGHT BEFORE AND THE POOR LOCATION OF THE ACARS CTL DISPLAY UNIT WHICH IN THIS PARTICULAR AIRPLANE IS IN THE FAR AFT PART OF THE CTR CTL PEDESTAL; CONSIDERABLY OUTSIDE THE PLT'S NORMAL FORWARD SCAN AREA. THE CHANCE OF THIS OR SIMILAR EVENT OCCURRING IN THE FUTURE COULD BE REDUCED BY AN INCREASED VIGILANCE AGAINST COMPLACENCY; IMPROVED PREFLT REST; AND POSSIBLY THE RELOCATION OF THE ACARS CTL UNIT. (THANK YOU FOR THE OPPORTUNITY TO PROVIDE NASA; THE FAA; AND THE AVIATION COMMUNITY WITH THIS INFO IN A NON-PUNITIVE ENVIRONMENT.)