Narrative:

We were cleared for the ILS xxl via a heading of 030 degrees and maintaining 3;000 ft till established. I remember the airspeed about 220 IAS at about 5 NM from the final approach fix and told the first officer to slow down. He slowed down and configured the aircraft for landing. We were handed over to tower; and cleared to land. I remember we were established on the localizer as we crossed the final fix. Next; I remember the localizer needle deviating 1 dot to the right and the and the glide slope not captured. I told him to increase his descent. I remember the autopilot not engaged but the flight director bars up. As he was correcting to his right to re-center the localizer; we got an EFIS comp mon; heading. Next; I noticed the FD in altitude mode and told first officer to increase descent rate. I turned the FD off so he could do that. Immediately after that I noticed my heading card was indicating about 360 degrees and the first officer had still not increased his descent and localizer had gone full scale deflection to the right! I then called for a missed approach. I remember tower instructing us to turn left to 280 degrees and maintain 4;000. We reconfigured the aircraft; got established on the new heading and reengaged the autopilot. Then tower asked us what our heading was and said that they had 'given us a heading of 040 degrees'. The first officer and I could have sworn that it was 280 degrees. That is when we both realized that the long duty day had put us into a fatigued condition and we were not as sharp as we should have been. Tower then assigned us a 280 heading and handed us back to approach. ATC asked the reason for the missed and I told her issues with the navigation and heading system. We slewed both heading cards and the EFIS comp mon message cleared. They vectored back for an ILS xxl and landed uneventfully.during taxi-in; we discussed what had happened and it occurred to us that a passenger cell phone 'could' have caused such a large anomaly. But we were also aware that we were over 14 hours of duty and were not that sharp. To make matters worse; the day had 2 very long breaks of 3:01 and 4:34 hours with no place to rest and relax. We talked about this the next day and realized how un-alert we were by the time we got to our last destination. It is apparent that after 14 hours of duty; a sharp instrument scan is impossible! Of course; we will never know why our heading cards moved so much.

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Original NASA ASRS Text

Title: An air carrier Captain reported that slewed compasses and fatigue contributed to an aborted approach and go-around.

Narrative: We were cleared for the ILS XXL via a heading of 030 degrees and maintaining 3;000 FT till established. I remember the airspeed about 220 IAS at about 5 NM from the final approach fix and told the First Officer to slow down. He slowed down and configured the aircraft for landing. We were handed over to Tower; and cleared to land. I remember we were established on the LOC as we crossed the final fix. Next; I remember the LOC needle deviating 1 dot to the right and the and the glide slope not captured. I told him to increase his descent. I remember the autopilot not engaged but the flight director bars up. As he was correcting to his right to re-center the localizer; we got an EFIS Comp Mon; heading. Next; I noticed the FD in altitude mode and told First Officer to increase descent rate. I turned the FD off so he could do that. Immediately after that I noticed my heading card was indicating about 360 degrees and the First Officer had still not increased his descent and LOC had gone full scale deflection to the right! I then called for a missed approach. I remember Tower instructing us to turn left to 280 degrees and maintain 4;000. We reconfigured the aircraft; got established on the new heading and reengaged the autopilot. Then Tower asked us what our heading was and said that they had 'given us a heading of 040 degrees'. The First Officer and I could have sworn that it was 280 degrees. That is when we both realized that the long duty day had put us into a fatigued condition and we were not as sharp as we should have been. Tower then assigned us a 280 heading and handed us back to approach. ATC asked the reason for the missed and I told her issues with the navigation and heading system. We slewed both heading cards and the EFIS COMP MON message cleared. They vectored back for an ILS XXL and landed uneventfully.During taxi-in; we discussed what had happened and it occurred to us that a passenger cell phone 'could' have caused such a large anomaly. But we were also aware that we were over 14 hours of duty and were not that sharp. To make matters worse; the day had 2 very long breaks of 3:01 and 4:34 hours with no place to rest and relax. We talked about this the next day and realized how un-alert we were by the time we got to our last destination. It is apparent that after 14 hours of duty; a sharp instrument scan is impossible! Of course; we will never know why our heading cards moved so much.

Data retrieved from NASA's ASRS site as of April 2012 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.