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An erj captain reported a false localizer capture on approach to 30L at stl. An air carrier aircraft behind reported normal indidcations.
| Attributes | |
| ACN | 874080 |
| Time | |
| Date | 201002 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | STL.Airport |
| State Reference | MO |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | EMB ERJ 145 ER&LR |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Route In Use | STAR QBall |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Inflight Event / Encounter Other / Unknown |
Narrative:
During the approach phase to stl we were given a heading to intercept the localizer for the ILS 30L. While we were on the heading (340; intercepting from the south via the qball arrival) we captured a 'false' localizer twice before intercepting the proper one. We knew it was an issue when the FMS display indicated our distance as approximately 12 miles from the approach course and then again about 5 miles from the approach course. The local cities (we could see visually straight down) we were over were around dupo; illinois and then again over sauget; illinois. We reported it to ATC and they queried an air carrier following us. They reported nothing unusual. I have seen this happen once before on a visual approach but never in IMC conditions. It is quite unsafe and would easily fool someone who is not intimately familiar with the area and the approaches at stl. Both times the aircraft was taken out of the navigation mode to keep it from following the incorrect localizer. I have heard from other pilots that they have experienced this as well. I cannot determine if it is a problem with our avionics on the E145. This should be investigated by the FAA. A clearance for the approach closer to the actual localizer may prevent further 'false captures.'
Original NASA ASRS Text
Title: An ERJ Captain reported a false localizer capture on approach to 30L at STL. An air carrier aircraft behind reported normal indidcations.
Narrative: During the approach phase to STL we were given a heading to intercept the localizer for the ILS 30L. While we were on the heading (340; intercepting from the south via the QBall arrival) we captured a 'false' localizer twice before intercepting the proper one. We knew it was an issue when the FMS display indicated our distance as approximately 12 miles from the approach course and then again about 5 miles from the approach course. The local cities (we could see visually straight down) we were over were around Dupo; Illinois and then again over Sauget; Illinois. We reported it to ATC and they queried an air carrier following us. They reported nothing unusual. I have seen this happen once before on a visual approach but never in IMC conditions. It is quite unsafe and would easily fool someone who is not intimately familiar with the area and the approaches at STL. Both times the aircraft was taken out of the NAV mode to keep it from following the incorrect localizer. I have heard from other pilots that they have experienced this as well. I cannot determine if it is a problem with our avionics on the E145. This should be investigated by the FAA. A clearance for the approach closer to the actual localizer may prevent further 'false captures.'
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.