Narrative:

On july 1990, en route to saipan at FL370, we discovered we were off course to the east. We were on a deviation route due to typhoon. After passing waypoint torsk, I moved the autoplt from INS to heading to dampen the oscillations the large heading change at torsk would cause. The autoplt limits the angle of bank to 10 degrees and hunts for the heading for 4 to 5 turns. My attention to navigating the aircraft was diverted by other duties and failed to return to it as planned. I did not make the other crew members aware of the autoplt's status when I left the flight deck a few mins later. Upon return, I again failed to return to navigating the aircraft and our fate was sealed. We became aware we were not at the proper place when we were nearing waypoint odezz. I immediately began a turn to the west in an attempt to return to course. We had been trying to contact guam center on 118.4 for about 1/2 hour. Saipan FSS was advised of our frequency problem and off course status and they gave us a new frequency to contact center. When communications were established with guam center, we were within 150 mi of saipan and the INS offset read 54 mi left of course. Confusion with communications and trying to explain our course deviation delayed descent into saipan until 75 mi from the airport. The controller was very helpful in assisting our descent with vectors and position advisories. He finally gave us a visibility approach to saipan airport when we were passing 15000', northwest of the field. We maintained visibility contact with the saipan airport during our descent while approximately 5 to 9 mi southwest on the runway 7 localizer. During the descent, a leading edge flap failed to extend. While solving this problem, some mistakes in communications occurred. He became concerned we were not reporting our position correctly. We reported over the airport when we were actually on the localizer, 5 to 9 mi southwest. We solved the flap problem, completed our descent at the OM, and landed at saipan uneventfully. I was unable to reach them by phone while at saipan. I had saipan FSS tell center I would call after landing in guam. Upon arrival, I called and spoke with the controller involved. I explained our mistake and thanked him for the help during our descent. I believe several factors contributed to this matter. My lack of awareness to the status of the autoplt. Distraction away from the duties of navigation. Not making the rest of the crew aware of the INS status. Flying at xb:00 am may have impaired my attention to details. Communication difficulty caused by equipment malfunction.

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Original NASA ASRS Text

Title: ACR WDB TRACK HEADING DEVIATION ON EXTENDED OVER WATER FLT.

Narrative: ON JULY 1990, ENRTE TO SAIPAN AT FL370, WE DISCOVERED WE WERE OFF COURSE TO THE E. WE WERE ON A DEV RTE DUE TO TYPHOON. AFTER PASSING WAYPOINT TORSK, I MOVED THE AUTOPLT FROM INS TO HDG TO DAMPEN THE OSCILLATIONS THE LARGE HDG CHANGE AT TORSK WOULD CAUSE. THE AUTOPLT LIMITS THE ANGLE OF BANK TO 10 DEGS AND HUNTS FOR THE HDG FOR 4 TO 5 TURNS. MY ATTN TO NAVIGATING THE ACFT WAS DIVERTED BY OTHER DUTIES AND FAILED TO RETURN TO IT AS PLANNED. I DID NOT MAKE THE OTHER CREW MEMBERS AWARE OF THE AUTOPLT'S STATUS WHEN I LEFT THE FLT DECK A FEW MINS LATER. UPON RETURN, I AGAIN FAILED TO RETURN TO NAVIGATING THE ACFT AND OUR FATE WAS SEALED. WE BECAME AWARE WE WERE NOT AT THE PROPER PLACE WHEN WE WERE NEARING WAYPOINT ODEZZ. I IMMEDIATELY BEGAN A TURN TO THE W IN AN ATTEMPT TO RETURN TO COURSE. WE HAD BEEN TRYING TO CONTACT GUAM CTR ON 118.4 FOR ABOUT 1/2 HR. SAIPAN FSS WAS ADVISED OF OUR FREQ PROB AND OFF COURSE STATUS AND THEY GAVE US A NEW FREQ TO CONTACT CTR. WHEN COMS WERE ESTABLISHED WITH GUAM CTR, WE WERE WITHIN 150 MI OF SAIPAN AND THE INS OFFSET READ 54 MI L OF COURSE. CONFUSION WITH COMS AND TRYING TO EXPLAIN OUR COURSE DEV DELAYED DSNT INTO SAIPAN UNTIL 75 MI FROM THE ARPT. THE CTLR WAS VERY HELPFUL IN ASSISTING OUR DSNT WITH VECTORS AND POS ADVISORIES. HE FINALLY GAVE US A VIS APCH TO SAIPAN ARPT WHEN WE WERE PASSING 15000', NW OF THE FIELD. WE MAINTAINED VIS CONTACT WITH THE SAIPAN ARPT DURING OUR DSNT WHILE APPROX 5 TO 9 MI SW ON THE RWY 7 LOC. DURING THE DSNT, A LEADING EDGE FLAP FAILED TO EXTEND. WHILE SOLVING THIS PROB, SOME MISTAKES IN COMS OCCURRED. HE BECAME CONCERNED WE WERE NOT RPTING OUR POS CORRECTLY. WE RPTED OVER THE ARPT WHEN WE WERE ACTUALLY ON THE LOC, 5 TO 9 MI SW. WE SOLVED THE FLAP PROB, COMPLETED OUR DSNT AT THE OM, AND LANDED AT SAIPAN UNEVENTFULLY. I WAS UNABLE TO REACH THEM BY PHONE WHILE AT SAIPAN. I HAD SAIPAN FSS TELL CTR I WOULD CALL AFTER LNDG IN GUAM. UPON ARR, I CALLED AND SPOKE WITH THE CTLR INVOLVED. I EXPLAINED OUR MISTAKE AND THANKED HIM FOR THE HELP DURING OUR DSNT. I BELIEVE SEVERAL FACTORS CONTRIBUTED TO THIS MATTER. MY LACK OF AWARENESS TO THE STATUS OF THE AUTOPLT. DISTR AWAY FROM THE DUTIES OF NAV. NOT MAKING THE REST OF THE CREW AWARE OF THE INS STATUS. FLYING AT XB:00 AM MAY HAVE IMPAIRED MY ATTN TO DETAILS. COM DIFFICULTY CAUSED BY EQUIP MALFUNCTION.

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.