Narrative:

We were on a heading for runway 35R from the south. We waited to call the airport in sight because a large cloud was shadowing the area making it difficult to identify the airport confidently. Once we called it in sight; cos approach control cleared us for the approach. As the pilot flying; I set the FAF altitude; but waited to arm the approach because I wanted to make sure we were close enough to get a good localizer signal and not have the aircraft do an 'south' turn to acquire the localizer. But as soon as I armed the approach; the aircraft started aggressively turning right; to the east; toward where the localizer was depicted on my pfd. However; my sight picture said we were still east of the centerline. The turn should have been gentle and to the left. Confused; I wasn't sure if I was lining up on the correct runway or if the wrong runway was loaded in the box. I clicked off the autopilot and the autothrust off to turn the aircraft back toward what we thought was 35R. As I scanned; I noticed the localizer still depicted a right turn and there was no GS (don't remember if it depicted GS armed). So we turned our flight directors off. We both checked the charts and saw that 109.1 was the correct frequency; but i-lpi was the wrong identifier. During the brief; I had noticed the identifier but thought nothing of it because we often pick up localizer identifiers from other airports when we brief before our initial descent. Often when expecting a visual approach we do not confirm the identifier; and when we do; it's the one found on the radnav page. As I flew; [the] pilot monitoring continued to check to make sure we were lined up on the correct runway. He noticed that the radnav indeed indicated the correct identifier; i-ahi. So I asked him to find out what i-lpi was from. I did not know of an airport to the east of us with a localizer that our aircraft might erroneously pick up. But I did know meadow lake airport was just east of cos and I did not want to mistake it for cos. Because of the cloud shadows; it was difficult to clearly see 35L and 31. He found the identifier and I heard him say it was for 35L. That didn't make sense either. Not sure if he misspoke or if I heard wrong; but it was actually for 17L. The right frequency but the wrong identifier did not make sense for 35L; so that confused me even more. In the confusion and distraction of trying to verify the runway; my approach became unstable. I felt I was almost stable so I continued. I believe I was stable at just after 1000 feet. But when the 'glide slope' aural warning began repeating; I got high on the PAPI; so I initiated a go around. Tower cleared us to 9000 [feet] and on downwind; again cleared us for the approach. We had time to verify the GS was for 17L so we briefed that we would silence the 'glide slope' warning when it occurred. We landed without further event. Most of the airports we fly into make sure the ILS is turned on even when performing visual approaches. If not; they include a NOTAM in the ATIS stating the ILS is OTS. ATIS [we received] did not have such a NOTAM. In a day of automation; when we find a NAVAID not working at the last minute; it causes adjustments which increase the workload at a critical point in the flight. Furthermore; having misleading navigational information is simply unsafe. Controllers could avoid confusion and potential safety problems by making sure the ILS is on correctly even on a VFR day; or at least notamed out of service. In discussing this event with other pilots; I was reminded that cos often does not have the ILS on. Perhaps a note in our blue pages mentioning that on a VFR day; do not expect the visual backed up by the ILS if indeed that is typical practice. I think our workload would have been greatly reduced if we had known why the identifiers did not match. Was there actually an aircraft computer malfunction; or is my conclusion that ATC had the wrong ILS on correct? If I had known for sure the cause; a simple query to tower making sure we were lined up on 35R may have reduced the workload and level of confusion. In the future; I will take note of times when the ILS identifier does not match on a visual backed up by the ILS. Also; I will ask my first officer to query the tower to verify the runway. Lastly; I will be prepared to silence the GS portion of the GPWS if I know the indications will be erroneous.

Related reports:

Google
 

Original NASA ASRS Text

Title: A320 Captain reported receiving erroneous 'fly to' information from ILS approach being used as backup to Visual approach being flown.

Narrative: We were on a heading for RWY 35R from the south. We waited to call the airport in sight because a large cloud was shadowing the area making it difficult to identify the airport confidently. Once we called it in sight; COS Approach Control cleared us for the approach. As the pilot flying; I set the FAF altitude; but waited to arm the approach because I wanted to make sure we were close enough to get a good LOC signal and not have the aircraft do an 'S' turn to acquire the LOC. But as soon as I armed the approach; the aircraft started aggressively turning right; to the east; toward where the LOC was depicted on my PFD. However; my sight picture said we were still east of the centerline. The turn should have been gentle and to the left. Confused; I wasn't sure if I was lining up on the correct runway or if the wrong runway was loaded in the box. I clicked off the Autopilot and the Autothrust off to turn the aircraft back toward what we thought was 35R. As I scanned; I noticed the LOC still depicted a right turn and there was no GS (don't remember if it depicted GS armed). So we turned our flight directors off. We both checked the charts and saw that 109.1 was the correct frequency; but I-LPI was the wrong identifier. During the brief; I had noticed the identifier but thought nothing of it because we often pick up LOC identifiers from other airports when we brief before our initial descent. Often when expecting a visual approach we do not confirm the identifier; and when we do; it's the one found on the RADNAV page. As I flew; [the] pilot monitoring continued to check to make sure we were lined up on the correct runway. He noticed that the RADNAV indeed indicated the correct identifier; I-AHI. So I asked him to find out what I-LPI was from. I did not know of an airport to the east of us with a LOC that our aircraft might erroneously pick up. But I did know Meadow Lake airport was just east of COS and I did not want to mistake it for COS. Because of the cloud shadows; it was difficult to clearly see 35L and 31. He found the identifier and I heard him say it was for 35L. That didn't make sense either. Not sure if he misspoke or if I heard wrong; but it was actually for 17L. The right frequency but the wrong identifier did not make sense for 35L; so that confused me even more. In the confusion and distraction of trying to verify the runway; my approach became unstable. I felt I was almost stable so I continued. I believe I was stable at just after 1000 feet. But when the 'Glide Slope' aural warning began repeating; I got high on the PAPI; so I initiated a go around. Tower cleared us to 9000 [feet] and on downwind; again cleared us for the approach. We had time to verify the GS was for 17L so we briefed that we would silence the 'Glide Slope' warning when it occurred. We landed without further event. Most of the airports we fly into make sure the ILS is turned on even when performing visual approaches. If not; they include a NOTAM in the ATIS stating the ILS is OTS. ATIS [we received] did not have such a NOTAM. In a day of automation; when we find a NAVAID not working at the last minute; it causes adjustments which increase the workload at a critical point in the flight. Furthermore; having misleading navigational information is simply unsafe. Controllers could avoid confusion and potential safety problems by making sure the ILS is on correctly even on a VFR day; or at least NOTAMed out of service. In discussing this event with other pilots; I was reminded that COS often does not have the ILS on. Perhaps a note in our blue pages mentioning that on a VFR day; do not expect the visual backed up by the ILS if indeed that is typical practice. I think our workload would have been greatly reduced if we had known why the identifiers did not match. Was there actually an aircraft computer malfunction; or is my conclusion that ATC had the wrong ILS on correct? If I had known for sure the cause; a simple query to Tower making sure we were lined up on 35R may have reduced the workload and level of confusion. In the future; I will take note of times when the ILS identifier does not match on a visual backed up by the ILS. Also; I will ask my First Officer to query the Tower to verify the runway. Lastly; I will be prepared to silence the GS portion of the GPWS if I know the indications will be erroneous.

Data retrieved from NASA's ASRS site 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.