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Air carrier captain reported led lighting on runway 18R at mem could affect depth perception in low visibility due to prism effect.
| Attributes | |
| ACN | 1590427 |
| Time | |
| Date | 201810 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | MEM.Airport |
| State Reference | TN |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Final Approach Landing |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain |
| Qualification | Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine |
| Events | |
| Anomaly | Ground Event / Encounter Other / Unknown |
Narrative:
On final approach into mem on RWY18R I noticed what looked like a faint displaced threshold. This made me think I had missed a NOTAM about some construction. As we flew closer to the runway I realized it was a double image just like I had noticed in okc about 6 months earlier. The double image is caused by the led lighting and it appears to be like a prism or holographic effect in the windows or the aircraft. I wear glasses and so during taxi in I raised my glasses and had the same double image and my first officer who does not wear glasses had the same double image. Also; the double image changes with seat position and is in the front and side windows. In okc earlier I thought it was caused by the lights being step 5 but the lights in mem were at mid-range intensity. This is a safety of flight issue that would affect your depth perception in a low visibility approach to a manual landing. I have never seen this in my entire career with regular incandescent lights. I think led lights somehow reacting with the different layers of the aircraft windows.
Original NASA ASRS Text
Title: Air carrier Captain reported LED lighting on Runway 18R at MEM could affect depth perception in low visibility due to prism effect.
Narrative: On final approach into MEM on RWY18R I noticed what looked like a faint displaced threshold. This made me think I had missed a NOTAM about some construction. As we flew closer to the runway I realized it was a double image just like I had noticed in OKC about 6 months earlier. The double image is caused by the LED lighting and it appears to be like a prism or holographic effect in the windows or the aircraft. I wear glasses and so during taxi in I raised my glasses and had the same double image and my First Officer who does not wear glasses had the same double image. Also; the double image changes with seat position and is in the front and side windows. In OKC earlier I thought it was caused by the lights being step 5 but the lights in MEM were at mid-range intensity. This is a safety of flight issue that would affect your depth perception in a low visibility approach to a manual landing. I have never seen this in my entire career with regular incandescent lights. I think LED lights somehow reacting with the different layers of the aircraft windows.
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.