Narrative:

After passing lyh, I turned outbound to fly the lyh R-219 on the majic arrival to clt. I noticed considerable course needle scalloping for the first 20 NM, which I attributed to the VOR cone of confusion. However the scalloping continued but not quite as severe. It would indicate on course centerline for several seconds, then traverse left and right. However, approaching the majic intersection, the CDI indicated that we were on course. Suddenly atl ARTCC assigned us a heading of south to join the arrival, stating that we were 5 mi off course. The CDI continued acting in this manner until approximately 10 NM north of clt, when it settled down to accurate, stable indications. I thought the problem was either a lyh VOR signal problem or instrument problem. However, the CDI gave normal indications in the clt area and during the entire flight to pit. A xchk of the first officer's CDI indicated the same. Callback conversation with reporter revealed the following information: reporter states the aircraft was a B737. He did not write up the problem because they started receiving vectors and were not using the vors that much. Nobody else seemed to be having problems that day, you can usually hear comments on the frequency if others are having difficulty. This sort of problem has occurred throughout his career but never to the extent of course deviation as this event. He was really disturbed to believe he could be so far off course and possibly interfere with other aircraft. No problems on departure, but they departed northwest and had come in from the northeast. He definitely feels it was a ground NAVAID problem.

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Original NASA ASRS Text

Title: B737 HAS SCALLOPING OF VOR NEEDLE ON ARR RTE.

Narrative: AFTER PASSING LYH, I TURNED OUTBOUND TO FLY THE LYH R-219 ON THE MAJIC ARR TO CLT. I NOTICED CONSIDERABLE COURSE NEEDLE SCALLOPING FOR THE FIRST 20 NM, WHICH I ATTRIBUTED TO THE VOR CONE OF CONFUSION. HOWEVER THE SCALLOPING CONTINUED BUT NOT QUITE AS SEVERE. IT WOULD INDICATE ON COURSE CTRLINE FOR SEVERAL SECONDS, THEN TRAVERSE L AND R. HOWEVER, APCHING THE MAJIC INTXN, THE CDI INDICATED THAT WE WERE ON COURSE. SUDDENLY ATL ARTCC ASSIGNED US A HEADING OF S TO JOIN THE ARR, STATING THAT WE WERE 5 MI OFF COURSE. THE CDI CONTINUED ACTING IN THIS MANNER UNTIL APPROX 10 NM N OF CLT, WHEN IT SETTLED DOWN TO ACCURATE, STABLE INDICATIONS. I THOUGHT THE PROB WAS EITHER A LYH VOR SIGNAL PROB OR INST PROB. HOWEVER, THE CDI GAVE NORMAL INDICATIONS IN THE CLT AREA AND DURING THE ENTIRE FLT TO PIT. A XCHK OF THE FO'S CDI INDICATED THE SAME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THE ACFT WAS A B737. HE DID NOT WRITE UP THE PROB BECAUSE THEY STARTED RECEIVING VECTORS AND WERE NOT USING THE VORS THAT MUCH. NOBODY ELSE SEEMED TO BE HAVING PROBS THAT DAY, YOU CAN USUALLY HEAR COMMENTS ON THE FREQ IF OTHERS ARE HAVING DIFFICULTY. THIS SORT OF PROB HAS OCCURRED THROUGHOUT HIS CAREER BUT NEVER TO THE EXTENT OF COURSE DEV AS THIS EVENT. HE WAS REALLY DISTURBED TO BELIEVE HE COULD BE SO FAR OFF COURSE AND POSSIBLY INTERFERE WITH OTHER ACFT. NO PROBS ON DEP, BUT THEY DEPARTED NW AND HAD COME IN FROM THE NE. HE DEFINITELY FEELS IT WAS A GND NAVAID PROB.

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.