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Air carrier captain experiences an erratic localizer signal during the ILS 26L approach to grr in VMC. The signal becomes stable inside three DME. The instability is a common occurrence on this approach and three others mentioned.
| Attributes | |
| ACN | 1148599 |
| Time | |
| Date | 201402 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | GRR.TRACON |
| State Reference | MI |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | ILS/VOR |
| Person 1 | |
| Function | Pilot Not Flying Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | ATC Issue All Types Aircraft Equipment Problem Less Severe |
Narrative:
This is a safety report to inform of erratic nav signals being received at grr. On approach into grr 26L; from about 10 DME to 3 DME; we received an erratic localizer signal. The CDI needle swung erratically from side to side; with the autopilot/flight director chasing the needle. We were in VMC conditions and disconnected the autopilot and hand flew the airplane to the airport. From 3 NM in; the signal was strong and normal. We reported the bad signal to grr tower. The aircraft was not written up as we had flown 2 coupled ILS approaches earlier in the day with no problems. From previous experience and [and many runway 26L approaches]; the 26L loc seems to give a signal that does not agree with our avionics. I have executed a missed approach before on this runway in the past for the same reasons only to shoot an approach to runway 35 with no problems. Similar erratic localizer signals can be found at lex 22; buf 05 and lga 04.
Original NASA ASRS Text
Title: Air Carrier Captain experiences an erratic localizer signal during the ILS 26L approach to GRR in VMC. The signal becomes stable inside three DME. The instability is a common occurrence on this approach and three others mentioned.
Narrative: This is a safety report to inform of erratic nav signals being received at GRR. On approach into GRR 26L; from about 10 DME to 3 DME; we received an erratic localizer signal. The CDI needle swung erratically from side to side; with the autopilot/flight director chasing the needle. We were in VMC conditions and disconnected the autopilot and hand flew the airplane to the airport. From 3 NM in; the signal was strong and normal. We reported the bad signal to GRR Tower. The aircraft was not written up as we had flown 2 coupled ILS approaches earlier in the day with no problems. From previous experience and [and many Runway 26L approaches]; the 26L Loc seems to give a signal that does not agree with our avionics. I have executed a missed approach before on this runway in the past for the same reasons only to shoot an approach to Runway 35 with no problems. Similar erratic LOC signals can be found at LEX 22; BUF 05 and LGA 04.
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.