CPR MLG FLC EXPERIENCES A GROSS NAV ERROR IN OCEANIC AIRSPACE DURING EXTENDED OVERWATER OP.

Narrative

SCHEDULED ITINERARY: KABE-KIAD-CYQX-LOWW. ACTUAL ITINERARY: KABE-KIAD-CYYT-LOWW. AT AM03Z; OCT/SAT/91; THE PLT MADE A POS RPT OF 50000N015000W TO SHANNON RADAR AND WAS NOTIFIED THAT THE ACFT'S ACTUAL POS WAS 51000N015000W (1 DEG N OF TRACK). THE AIRCREW IMMEDIATELY STARTED CHKING THE ONBOARD NAV SYS (DUAL INS; VLF OMEGA). ALL SYS WERE FOUND TO BE FUNCTIONING PROPERLY AT THE TIME. FURTHER INVESTIGATION DISCLOSED THE POS 50N015W HAD BEEN INSTALLED AS 51N015W INTO BOTH INERTIAL NAV SYS. CONTRIBUTING FACTORS: APPROX 45 MINS OUT OF CYQX (GANDER NFLD) THE AIRCREW DISCOVERED LNDG WX WAS BELOW MINS AND ELECTED TO DIVERT TO CYYT (ST JOHNS NFLD). DUE TO OTHER DIVERSIONS; THE ACFT HAD TO HOLD AT THE OM PRIOR TO COMMENCING APCH INTO DETERIORATING WX CONDITIONS. DURING APCH; ACFT ENCOUNTERED LIGHT TO MODERATE TURB AND WIND SHEAR. THE AIRCREW THEN HAD TO COORDINATE HANDLING (FUEL; CUSTOMS; ETC); RTING CLRNC AND PAX COMFORT. THE STRESSFUL ENVIRONMENT; LONG DAY; TASK SATURATION; SENSE OF URGENCY TO EXPEDITE DEP REQUIREMENTS AND PROGRAMMING TOTAL RERTE INTO THE INERTIAL NAV SYS LED TO THE RTE NAV ERROR. BOTH PLTS NORMALLY COORDINATE WAYPOINT INSTALLATION INTO THE INERTIAL NAV SYS. DUE TO THE MULTIPLE INTERRUPTIONS IN NORMAL COCKPIT SEQUENCES ON THE GND; CREW COORD DETERIORATED ALLOWING THE NAV INPUT ERROR TO GO UNNOTICED. CORRECTIVE ACTIONS: A) REEMPHASIZE THE NECESSITY FOR CREW COORD AND STANDARDIZED PROCS FOR ACFT OP FROM PREFLT; GND OPS; ALL PHASES OF FLT AND POST-FLT DUTIES. B) BOTH PLTS SHOULD CHK INERTIAL NAV PROGRAMMING INPUTS ON THE GND AND AGAIN FOLLOWING OCEANIC CLRNC RECEPTION. C) PLTS SHOULD PLOT RTING CLRNC ON AN OCEANIC PLANNING CHART (OPC 1) OR ITS EQUIVALENT AND PLOT THE INERTIAL AND VLF-OMEGA POS AT EACH WAYPOINT TO ENSURE ACFT REMAINS WITHIN THE MNPS NAV PERFORMANCE PARAMETERS. D) PLTS SHOULD RECEIVE ANNUAL TRAINING IN THE OP OF UNITED STATES REGISTERED CIVIL ACFT OUTSIDE OF THE UNITED STATES (SPECIFICALLY N ATLANTIC MNPS AIRSPACE).