Narrative:

On approach to dfw we were given a close turn in with instructions to intercept the localizer and clearance for the ILS. We intercepted the localizer and tracked it inbound as instructed (runway 35R) until we acquired the runway visually at about 6 mi. We noticed that although the locs and GS indicators were showing on course, we were actually well left of runway centerline. We continued on visually and at about 4 mi the localizer indicator went to full scale deflection and began showing proper indications. I feel that this display error was caused by some sort of electromagnetic interference from inside our aircraft.

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Original NASA ASRS Text

Title: FLC OF LGT SUSPECTED ELECTRONIC INTERFERENCE TO THE ILS VOR LOC INDICATOR SINCE THE INDICATOR WAS ERRATIC AND UNRELIABLE UNTIL JUST BEFORE LNDG. FINAL APCH OVERSHOT DURING VISUAL APCH.

Narrative: ON APCH TO DFW WE WERE GIVEN A CLOSE TURN IN WITH INSTRUCTIONS TO INTERCEPT THE LOC AND CLRNC FOR THE ILS. WE INTERCEPTED THE LOC AND TRACKED IT INBOUND AS INSTRUCTED (RWY 35R) UNTIL WE ACQUIRED THE RWY VISUALLY AT ABOUT 6 MI. WE NOTICED THAT ALTHOUGH THE LOCS AND GS INDICATORS WERE SHOWING ON COURSE, WE WERE ACTUALLY WELL L OF RWY CTRLINE. WE CONTINUED ON VISUALLY AND AT ABOUT 4 MI THE LOC INDICATOR WENT TO FULL SCALE DEFLECTION AND BEGAN SHOWING PROPER INDICATIONS. I FEEL THAT THIS DISPLAY ERROR WAS CAUSED BY SOME SORT OF ELECTROMAGNETIC INTERFERENCE FROM INSIDE OUR ACFT.

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.