Narrative:

We have aircraft reports of unexpected deflection when flying the ILS runway 5 approach at buf. These reports date back to the spring of 2010. We have had 13 reports in the last five weeks. Most of the aircraft appear to be E145. Today an E145; reported a 20 to 30 degree roll after auto acquiring the localizer to runway 5. It is note worthy that aircraft flying the approach manually have reported seeing something on occasion but do not respond as it appears and returns to normal very rapidly. But aircraft that auto acquire the aircraft responds to this and they experience a roll right or left and back. The localizer antenna when installed was noted to be lower than normal; 'but it should work.' flight check has passed it and experienced this condition while flying the approach. The solutions offered have been to move the localizer antenna. Recommendation; while a permanent solution is worked on; I believe a NOTAM should be issued by flight standards that instructs all aircraft to fly the approach manually; 'do not auto acquire.'

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Original NASA ASRS Text

Title: BUF Supervisor Controller described reports from several aircraft regarding a roll experienced on the ILS 5 Approach during ILS auto acquisition. The reporter indicated the anomaly was most often experienced with EMB-145 aircraft and suggested a NOTAM be issued instructing aircraft not to auto acquire the ILS.

Narrative: We have aircraft reports of unexpected deflection when flying the ILS Runway 5 approach at BUF. These reports date back to the spring of 2010. We have had 13 reports in the last five weeks. Most of the aircraft appear to be E145. Today an E145; reported a 20 to 30 degree roll after auto acquiring the localizer to Runway 5. It is note worthy that aircraft flying the approach manually have reported seeing something on occasion but do not respond as it appears and returns to normal very rapidly. But aircraft that auto acquire the aircraft responds to this and they experience a roll right or left and back. The localizer antenna when installed was noted to be lower than normal; 'but it should work.' Flight check has passed it and experienced this condition while flying the approach. The solutions offered have been to move the localizer antenna. Recommendation; while a permanent solution is worked on; I believe a NOTAM should be issued by Flight Standards that instructs all aircraft to fly the approach manually; 'do not auto acquire.'

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.