NAV ERROR. FO ON A B727-200 RPTS ON THE INACCURACY OF THE OMEGA SYS IN USE THAT DAY FROM BOS TO ARUBA. BY THE TIME THEY ARRIVED AT ZMA CTL AREA THEY WERE SOME 85 MI W OF PLANNED COURSE. FO CITES THE CAPT AS BEING PARTLY RESPONSIBLE FOR NOT INSURING A LAND DEP POINT FOR AN ACCURACY CHK OF THE OMEGA.

Narrative

TO BEGIN WITH; THE FLT PLAN RTE NEEDS TO BE STATED. I FEEL THE INITIAL FAILURE TO FLY THE FLT PLAN RTE MAY HAVE LED TO THE EVENT. DEP POINT: BOS. ARR POINT: ARUBA. FLT PLAN/CLRNC: LOGAN 1 LUCOS SEY 067 SEY DIRECT HTO DIRECT RANCO DIRECT KUPEC A554 LAMER DIRECT SEKAR DIRECT PTA UW7 BEROX A567 TNCA. THE ACFT LONG RANGE NAV SYS IS OMEGA. A STANDARD PRACTICE WHEN USING OMEGA IS TO POSITIVELY FIX THE POS BY OVERFLYING A VOR OR NDB PRIOR TO GOING ON AN OCEANIC RTE. THIS IS WHERE I BELIEVE THE PROB INITIALLY OCCURRED. UPON REACHING LUCOS INTXN ON THE LOGAN 1 DEP FROM BOS; ZBW CLRED THE FLT DIRECT TO RANCO INTXN. THE CAPT OF THE FLT ACCEPTED THIS CLRNC. I QUESTIONED WHETHER WE SHOULD ACCEPT THIS BECAUSE WE NEEDED TO GO OVER A GATE AND POSITIVELY FIX OUR POS WITH THE OMEGA. WHAT FOLLOWED WAS A RATHER INTENSE DISCUSSION OVER WHAT WAS THE CORRECT AND PROPER PROC WHEN FLYING WITH OMEGA. THE CAPT'S ARGUMENT WAS THAT HIS MAP AND PLOTTER SHOWED THAT THE OMEGA COURSE AND DISTANCE WERE INDEED CORRECT. I COULD NOT ARGUE WITH THIS EXCEPT TO SAY THAT WITHOUT A POSITIVE FIX ON THE OMEGA; THE SYS TENDED TO WANDER. AFTER WE BEGAN TO GO DIRECT RANCO; I COUPLED THE AUTOPLT TO THE OMEGA. UPON REACHING RANCO; WE TRIED TO TRIANGULATE THE POS WITH BEARINGS FROM HTO AND SIE VORS. THESE BEARINGS SHOWED THE ACFT TO BE A LITTLE W AND S OF COURSE; COMPARED TO THE OMEGA. WE CORRECTED FOR THESE INDICATIONS AND THEN PROCEEDED TO FLY DIRECT KUPEC-A554 ETC. IT MUST BE STATED HERE THAT AFTER RANCO; THE FLT LOSES RADAR CONTACT AND MUST MAKE POS RPTS. THE OMEGA AND AUTOPLT APPEARED TO BE OPERATING PROPERLY. EACH POS CAME WITHIN 2-3 MINS OF WHAT THE COMPUTER FLT PLAN SHOWED. WE GAVE OUR POS RPTS ACCORDING TO THE INFO OFF THE OMEGA AND XCHKED WITH THE FLT PLAN. APCHING LAMER INTXN ON A554; THE FLT WAS SUPPOSED TO CONTACT ZMA. AFTER INITIAL CONTACT; ZMA ASKED FOR AN IDENT. THEY PROCEEDED TO TELL US WE WERE 5 MI SE OF LETON INTXN. LETON IS APPROX 90 MI W OF LAMER. AT THIS POINT WE RPTED AN OMEGA VLF NAV FAILURE. WE WERE ABLE TO CONTINUE THE FLT VIA VOR NAV TO THE DEST. IN SUMMARY: I FEEL THE PROB AROSE BY NOT TAKING A POSITIVE FIX. BY NOT BEING IN RADAR CONTACT; THE FLT WAS NOT ABLE TO BE CORRECTED FOR COURSE ERROR. I BELIEVE THE OMEGA SYS IS TOO INACCURATE AND SHOULD NOT BE USED FOR LONG RANGE NAV. I BELIEVE THE CAPT'S LACK OF KNOWLEDGE ON THE OMEGA SYS ENHANCED A BAD JUDGEMENT ON HIS PART; IE; PROCEED DIRECT RANCO WITHOUT A POSITIVE FIX. I ALSO FEEL HIS INABILITY TO LISTEN TO THE CREW AND THEREFORE EXERCISE CRM CONTRIBUTED TO THIS EVENT.