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A B747-400 intercepted a false localizer at an unreported airport. The flight crew disconnected autoflight systems and reestablished the intercept heading until capturing the localizer and completed the approach manually.
| Attributes | |
| ACN | 857049 |
| Time | |
| Date | 200910 |
| Environment | |
| Flight Conditions | Marginal |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Navigational Equipment and Processing |
| Person 1 | |
| Function | Pilot Flying Captain |
| Experience | Flight Crew Last 90 Days 164 Flight Crew Total 13738 Flight Crew Type 8577 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Track / Heading All Types |
Narrative:
On heading 340 cleared to intercept and commence ILS 7L. Autopilot intercepted a false localizer about 1.5 miles before center line of 7L. Localizer diamond pegged to the left of scale and blank. Immediately when recognized clicked off autopilot and had copilot heading select to correct center line and also turn off flight directors and re-initiate the approach. Intercept of correct localizer occurred prior to final fix. Controller called once to say appeared we were right of course and we told him correcting. I had heard of false intercepts but had never seen one. Did not know what to expect; i.e. A diamond blank and pegged to left of scale. If this happened to anyone new to the airplane the event could have had a tragic outcome because the visibility was very poor.
Original NASA ASRS Text
Title: A B747-400 intercepted a false localizer at an unreported airport. The flight crew disconnected autoflight systems and reestablished the intercept heading until capturing the localizer and completed the approach manually.
Narrative: On heading 340 cleared to intercept and commence ILS 7L. Autopilot intercepted a false localizer about 1.5 miles before center line of 7L. Localizer diamond pegged to the left of scale and blank. Immediately when recognized clicked off autopilot and had copilot heading select to correct center line and also turn off flight directors and re-initiate the approach. Intercept of correct localizer occurred prior to Final Fix. Controller called once to say appeared we were right of course and we told him correcting. I had heard of false intercepts but had never seen one. Did not know what to expect; i.e. a diamond blank and pegged to left of scale. If this happened to anyone new to the airplane the event could have had a tragic outcome because the visibility was very poor.
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.