Narrative:

I was flying home from chatham, ma, to northampton, at night. I thought I was flying toward providence, ri, arsa. Saw a big city and realized I might be on outskirts of boston by mistake when air traffic above me was large aircraft (3 or 4). At this time I was at 6800' and realized my compass was reading very wrong. This was my first flight since a very expensive annual inspection. I was trying to fly the putnam VOR and the needle kept going farther off center the more I corrected. I realized I was going in a circle and that I was way off course and may have penetrated the bos TCA. I flew south by visibility means (my compass said east) and got back on course. I then called pvd approach and told them of compass problems and asked for vectors to westover airport which is near northampton. I had no trouble to speak of after that. If I did get into the bos TCA I did not dare to get to 7000' because of traffic above me. There was nobody below me so I stayed where I was and got out of the area. I feel that my compass got magnetized during the many repairs to the airplane during the annual (the first since I owned the plane). When I reset the dg to the errant compass I threw everything off. Since I did not know the cape cod area very well I did not realize I was off course until it became obvious. For safety's sake, I think repair stations should be required to properly swing the compass of every aircraft that they give an annual inspection to, and to make appropriate corrections to compass correction card. A bad compass would show up at this time. My VOR received is still being looked at, so no comment on that now.

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Original NASA ASRS Text

Title: DISORIENTATION OF SMA ACFT PLT AND SUBSEQUENT PENETRATION OF TCA. REPORTER CITES COMPASS PROBLEM ERROR MAJOR CAUSE.

Narrative: I WAS FLYING HOME FROM CHATHAM, MA, TO NORTHAMPTON, AT NIGHT. I THOUGHT I WAS FLYING TOWARD PROVIDENCE, RI, ARSA. SAW A BIG CITY AND REALIZED I MIGHT BE ON OUTSKIRTS OF BOSTON BY MISTAKE WHEN AIR TFC ABOVE ME WAS LARGE ACFT (3 OR 4). AT THIS TIME I WAS AT 6800' AND REALIZED MY COMPASS WAS READING VERY WRONG. THIS WAS MY FIRST FLT SINCE A VERY EXPENSIVE ANNUAL INSPECTION. I WAS TRYING TO FLY THE PUTNAM VOR AND THE NEEDLE KEPT GOING FARTHER OFF CENTER THE MORE I CORRECTED. I REALIZED I WAS GOING IN A CIRCLE AND THAT I WAS WAY OFF COURSE AND MAY HAVE PENETRATED THE BOS TCA. I FLEW S BY VIS MEANS (MY COMPASS SAID E) AND GOT BACK ON COURSE. I THEN CALLED PVD APCH AND TOLD THEM OF COMPASS PROBS AND ASKED FOR VECTORS TO WESTOVER ARPT WHICH IS NEAR NORTHAMPTON. I HAD NO TROUBLE TO SPEAK OF AFTER THAT. IF I DID GET INTO THE BOS TCA I DID NOT DARE TO GET TO 7000' BECAUSE OF TFC ABOVE ME. THERE WAS NOBODY BELOW ME SO I STAYED WHERE I WAS AND GOT OUT OF THE AREA. I FEEL THAT MY COMPASS GOT MAGNETIZED DURING THE MANY REPAIRS TO THE AIRPLANE DURING THE ANNUAL (THE FIRST SINCE I OWNED THE PLANE). WHEN I RESET THE DG TO THE ERRANT COMPASS I THREW EVERYTHING OFF. SINCE I DID NOT KNOW THE CAPE COD AREA VERY WELL I DID NOT REALIZE I WAS OFF COURSE UNTIL IT BECAME OBVIOUS. FOR SAFETY'S SAKE, I THINK REPAIR STATIONS SHOULD BE REQUIRED TO PROPERLY SWING THE COMPASS OF EVERY ACFT THAT THEY GIVE AN ANNUAL INSPECTION TO, AND TO MAKE APPROPRIATE CORRECTIONS TO COMPASS CORRECTION CARD. A BAD COMPASS WOULD SHOW UP AT THIS TIME. MY VOR RECEIVED IS STILL BEING LOOKED AT, SO NO COMMENT ON THAT NOW.

Data retrieved from NASA's ASRS site as of August 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.