Airbus Industrie Undifferentiated or Other Model
Confusion
No Specific Anomaly Occurred All Types
General None Reported / Taken
Airport; Human Factors
General Safety Concern-  VASI for Runway 23L GSO. There is a lighted windsock adjacent to and in close proximity to the VASI for 28L. The windsock has a RED light mounted on top. When you are on ILS 23L approach and lined up on LOC and Glideslope; at BRANT OM the RED windsock light actually is visually aligned with the leftmost of the VASI light system.  The RED light on the windsock is actually so bright it overpowers being able to see the leftmost WHITE light on the VASI; causing the leftmost light of the VASI to appear either RED or PINK. This phenomena occurs from BRANT OM to around 500 feet AGL where the windsock light is no longer in alignment with the visual sight path to the VASI; and the effect diminished as the lights diverge. When you are on glide path from OM BRANT to 500 AGL the normal  WHITE-WHITE-RED-RED of the VASI appears to be RED-WHITE-RED-RED. Windsock should be relocated away from VASI system.
Air Carrier pilot reports that a red light atop the windsock for Runway 23L at GSO aligns precisely with the left most VASI light for the same runway. This means that an on glide path indication is red (pink); white; red; red from the FAF to about 500 feet AGL; causing confusion.