Narrative:

Departed phf for rdu at XA40. The flight proceeded smoothly. The flight was cleared for an ILS 23L approach at rdu. Just outside the OM the localizer course began deviating left and right of course. All 3 navigation radios were tuned and idented to 108.50, the localizer frequency. All localizer needles would more together as if they were synchronized. As we broke out of the clouds we found ourselves between runways 23L and 23R. ATC advised no sep rules were violated. Investigation into the aircraft revealed this to be the third known incident involving aircraft with localizer problems in the last 2 weeks.

Google
 

Original NASA ASRS Text

Title: ACR SMT TRACK DEVIATION CAUSED BY FAULTY NAVIGATION EQUIPMENT.

Narrative: DEPARTED PHF FOR RDU AT XA40. THE FLT PROCEEDED SMOOTHLY. THE FLT WAS CLRED FOR AN ILS 23L APCH AT RDU. JUST OUTSIDE THE OM THE LOC COURSE BEGAN DEVIATING LEFT AND RIGHT OF COURSE. ALL 3 NAV RADIOS WERE TUNED AND IDENTED TO 108.50, THE LOC FREQ. ALL LOC NEEDLES WOULD MORE TOGETHER AS IF THEY WERE SYNCHRONIZED. AS WE BROKE OUT OF THE CLOUDS WE FOUND OURSELVES BTWN RWYS 23L AND 23R. ATC ADVISED NO SEP RULES WERE VIOLATED. INVESTIGATION INTO THE ACFT REVEALED THIS TO BE THE THIRD KNOWN INCIDENT INVOLVING ACFT WITH LOC PROBS IN THE LAST 2 WKS.

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.