Narrative:

Operating flight from san juan to newark on sep/xx/95, we discovered ourselves 130 NM off course prior to a reporting point. We immediately corrected our heading to get back on course, monitoring TCASII for any possible conflict with other traffic (there was none) and re-estimating our next point. In reconstructing the chain of events, a lack of discipline in cockpit management seems to be the most likely cause. We were on course, northbound on R763, approaching sarje intersection. The captain turned slightly left to avoid a thunderstorm near sarje. We passed abeam sarje, 3-4 mi left on a parallel track, and I made a position report. I left the cockpit to relieve myself and returned a few moments later. The captain then left for the same reason and returned a few moments later. The next reporting point, coran, had been omitted from the omega during initial programming. The captain had not realized it was a mandatory point, and I had neglected to question him. It was only an 18 min leg to coran and instead of reprogramming the omega I decided to monitor the position function and call passing the coran latitude. Neither pilot had noticed any deviations or problems, since the equipment had been operating normally, and all estimates had matched our actual position. Approaching coran, I began to monitor position on the omega, waiting to cross coran. I suddenly noticed we were well left and told the captain. Not immediately realizing how far off we were, he turned toward course, but I re-emphasized how far left we were, and he made a larger correction. Instead of being at west 73 degree 27900 ft we were at west 76 degrees 30000 ft, or about 130 NM left. I then attempted to contact ny oceanic on primary and secondary HF frequencys, but could not. After several tries, ny contacted us through SELCAL and there was much confusion as we tried to determine how we strayed from course so far, and revise estimates to bacus as we returned to course. We were on course again south of bacus, contacted ZDC as directed, and continued to newark without incident. Without any crew member noticing, the autoplt became disconnected from the automatic navigation, or was never re-connected after our WX deviation. This seems more likely, since both pilots took turns leaving the cockpit during that time frame. Contributing factors were not programming the omega with all waypoints, and not monitoring the progress properly. Normal monitoring includes xtrack error as well as time and position, but I was 'tuned in to' and concentrating on watching the latitude at coran. Familiarity with a route creates a comfort factor and I have flown this route many times. Complacency is something we guard against, but I am afraid it contributed to this problem. Supplemental information from acn 316317: about 40 south of sarje I removed the autoplt from automatic navigation and made a left 5 degree correction to pass west of the cell over sarje. I recall planning to change the omega navigation leg from 6-7 to 0-7 since we were so close to the track. I was thinking I had to do this before I left the cockpit to relieve myself. I believe while the first officer was out of the cockpit I made my track change to the omega. I didn't observe anything wrong. As I recall, I was only looking out the windscreen thinking about 'stuff' for what I thought was only a few mins. Apparently, the distraction of my own and the first officer's physiological needs was the reason I missed returning the autoplt to omega navigation. I snapped up the xtrack error and couldn't believe my eyes. 130 degrees left of track. I now made my most grievous judgement error. I did not inform ATC of our location. Hindsight tells me I should have declared a navigation emergency. I can only suppose that one of two things could have happened. The turn knob was not in the '0' detent and the aircraft was turning unnoticed. The manual heading function was malfunctioning and the heading was sluing to the left imperceptibly. Contributing factors: fatigue. Poor previous night's sleep. Skipped numbering the coran waypoint when setting up the route for the omega (I was thinking it was an optional fix). Not challenged by first officer. Unaware first officer was making position report at coran without correcting the waypoint input in theomega. Poor cockpit discipline regarding checking equipment before and after leaving the cockpit. Failed to use my own personal GPS. Failed to change my flight guidance display to heading to remind me that the navigation function was disengaged. Concern about my wife as she was having an mri of her aorta for symptoms relating to her stroke. My own health as the day before I was informed my knee would require surgery. Recommendations: better crew briefing regarding pitfalls of antiquated navigation system. Use all equipment available (GPS). Aural off course warning quite like the off altitude warning incorporated into navigation system.

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Original NASA ASRS Text

Title: GROSS NAV ERROR DURING AN OVERWATER OP. HDG TRACK POS DEV.

Narrative: OPERATING FLT FROM SAN JUAN TO NEWARK ON SEP/XX/95, WE DISCOVERED OURSELVES 130 NM OFF COURSE PRIOR TO A RPTING POINT. WE IMMEDIATELY CORRECTED OUR HDG TO GET BACK ON COURSE, MONITORING TCASII FOR ANY POSSIBLE CONFLICT WITH OTHER TFC (THERE WAS NONE) AND RE-ESTIMATING OUR NEXT POINT. IN RECONSTRUCTING THE CHAIN OF EVENTS, A LACK OF DISCIPLINE IN COCKPIT MGMNT SEEMS TO BE THE MOST LIKELY CAUSE. WE WERE ON COURSE, NBOUND ON R763, APCHING SARJE INTXN. THE CAPT TURNED SLIGHTLY L TO AVOID A TSTM NEAR SARJE. WE PASSED ABEAM SARJE, 3-4 MI L ON A PARALLEL TRACK, AND I MADE A POS RPT. I LEFT THE COCKPIT TO RELIEVE MYSELF AND RETURNED A FEW MOMENTS LATER. THE CAPT THEN LEFT FOR THE SAME REASON AND RETURNED A FEW MOMENTS LATER. THE NEXT RPTING POINT, CORAN, HAD BEEN OMITTED FROM THE OMEGA DURING INITIAL PROGRAMMING. THE CAPT HAD NOT REALIZED IT WAS A MANDATORY POINT, AND I HAD NEGLECTED TO QUESTION HIM. IT WAS ONLY AN 18 MIN LEG TO CORAN AND INSTEAD OF REPROGRAMMING THE OMEGA I DECIDED TO MONITOR THE POS FUNCTION AND CALL PASSING THE CORAN LAT. NEITHER PLT HAD NOTICED ANY DEVS OR PROBS, SINCE THE EQUIP HAD BEEN OPERATING NORMALLY, AND ALL ESTIMATES HAD MATCHED OUR ACTUAL POS. APCHING CORAN, I BEGAN TO MONITOR POS ON THE OMEGA, WAITING TO CROSS CORAN. I SUDDENLY NOTICED WE WERE WELL L AND TOLD THE CAPT. NOT IMMEDIATELY REALIZING HOW FAR OFF WE WERE, HE TURNED TOWARD COURSE, BUT I RE-EMPHASIZED HOW FAR L WE WERE, AND HE MADE A LARGER CORRECTION. INSTEAD OF BEING AT W 73 DEG 27900 FT WE WERE AT W 76 DEGS 30000 FT, OR ABOUT 130 NM L. I THEN ATTEMPTED TO CONTACT NY OCEANIC ON PRIMARY AND SECONDARY HF FREQS, BUT COULD NOT. AFTER SEVERAL TRIES, NY CONTACTED US THROUGH SELCAL AND THERE WAS MUCH CONFUSION AS WE TRIED TO DETERMINE HOW WE STRAYED FROM COURSE SO FAR, AND REVISE ESTIMATES TO BACUS AS WE RETURNED TO COURSE. WE WERE ON COURSE AGAIN S OF BACUS, CONTACTED ZDC AS DIRECTED, AND CONTINUED TO NEWARK WITHOUT INCIDENT. WITHOUT ANY CREW MEMBER NOTICING, THE AUTOPLT BECAME DISCONNECTED FROM THE AUTO NAV, OR WAS NEVER RE-CONNECTED AFTER OUR WX DEV. THIS SEEMS MORE LIKELY, SINCE BOTH PLTS TOOK TURNS LEAVING THE COCKPIT DURING THAT TIME FRAME. CONTRIBUTING FACTORS WERE NOT PROGRAMMING THE OMEGA WITH ALL WAYPOINTS, AND NOT MONITORING THE PROGRESS PROPERLY. NORMAL MONITORING INCLUDES XTRACK ERROR AS WELL AS TIME AND POS, BUT I WAS 'TUNED IN TO' AND CONCENTRATING ON WATCHING THE LAT AT CORAN. FAMILIARITY WITH A RTE CREATES A COMFORT FACTOR AND I HAVE FLOWN THIS RTE MANY TIMES. COMPLACENCY IS SOMETHING WE GUARD AGAINST, BUT I AM AFRAID IT CONTRIBUTED TO THIS PROB. SUPPLEMENTAL INFO FROM ACN 316317: ABOUT 40 S OF SARJE I REMOVED THE AUTOPLT FROM AUTO NAV AND MADE A L 5 DEG CORRECTION TO PASS W OF THE CELL OVER SARJE. I RECALL PLANNING TO CHANGE THE OMEGA NAV LEG FROM 6-7 TO 0-7 SINCE WE WERE SO CLOSE TO THE TRACK. I WAS THINKING I HAD TO DO THIS BEFORE I LEFT THE COCKPIT TO RELIEVE MYSELF. I BELIEVE WHILE THE FO WAS OUT OF THE COCKPIT I MADE MY TRACK CHANGE TO THE OMEGA. I DIDN'T OBSERVE ANYTHING WRONG. AS I RECALL, I WAS ONLY LOOKING OUT THE WINDSCREEN THINKING ABOUT 'STUFF' FOR WHAT I THOUGHT WAS ONLY A FEW MINS. APPARENTLY, THE DISTR OF MY OWN AND THE FO'S PHYSIOLOGICAL NEEDS WAS THE REASON I MISSED RETURNING THE AUTOPLT TO OMEGA NAV. I SNAPPED UP THE XTRACK ERROR AND COULDN'T BELIEVE MY EYES. 130 DEGS L OF TRACK. I NOW MADE MY MOST GRIEVOUS JUDGEMENT ERROR. I DID NOT INFORM ATC OF OUR LOCATION. HINDSIGHT TELLS ME I SHOULD HAVE DECLARED A NAV EMER. I CAN ONLY SUPPOSE THAT ONE OF TWO THINGS COULD HAVE HAPPENED. THE TURN KNOB WAS NOT IN THE '0' DETENT AND THE ACFT WAS TURNING UNNOTICED. THE MANUAL HDG FUNCTION WAS MALFUNCTIONING AND THE HDG WAS SLUING TO THE L IMPERCEPTIBLY. CONTRIBUTING FACTORS: FATIGUE. POOR PREVIOUS NIGHT'S SLEEP. SKIPPED NUMBERING THE CORAN WAYPOINT WHEN SETTING UP THE RTE FOR THE OMEGA (I WAS THINKING IT WAS AN OPTIONAL FIX). NOT CHALLENGED BY FO. UNAWARE FO WAS MAKING POS RPT AT CORAN WITHOUT CORRECTING THE WAYPOINT INPUT IN THEOMEGA. POOR COCKPIT DISCIPLINE REGARDING CHKING EQUIP BEFORE AND AFTER LEAVING THE COCKPIT. FAILED TO USE MY OWN PERSONAL GPS. FAILED TO CHANGE MY FLT GUIDANCE DISPLAY TO HDG TO REMIND ME THAT THE NAV FUNCTION WAS DISENGAGED. CONCERN ABOUT MY WIFE AS SHE WAS HAVING AN MRI OF HER AORTA FOR SYMPTOMS RELATING TO HER STROKE. MY OWN HEALTH AS THE DAY BEFORE I WAS INFORMED MY KNEE WOULD REQUIRE SURGERY. RECOMMENDATIONS: BETTER CREW BRIEFING REGARDING PITFALLS OF ANTIQUATED NAV SYS. USE ALL EQUIP AVAILABLE (GPS). AURAL OFF COURSE WARNING QUITE LIKE THE OFF ALT WARNING INCORPORATED INTO NAV SYS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.