Externally Illuminated Windsock

An Externally Illuminated Windsock is a wind cone assembly that uses external floodlights or spotlights mounted on the mast or nearby structures to illuminate the windsock from the outside. This is the traditional and most common method of windsock illumination. The light sources are typically LED or halogen floodlights positioned at the base of the mast or on separate poles, aimed upward to bathe the entire windsock in light. This design offers several advantages: easy lamp replacement (no need to enter the mast), the ability to use standard, off‑the‑shelf lighting fixtures, and the flexibility to adjust the beam angle and intensity to suit different wind cone sizes and locations. External illumination is also easier to inspect and maintain, as all lighting components are accessible at ground level or on the mast's exterior.

External illumination exists to keep a windsock visible at night using simple, easily maintained equipment: because the light source sits outside the mast, technicians can inspect, adjust, or replace it from ground level without accessing the interior of the structure, which keeps maintenance straightforward and downtime short if a lamp fails. This practicality is a real safety consideration in its own right, since a windsock that goes dark at night because of a hard-to-service internal fault loses its value exactly when pilots most need a wind reference.

The flexibility to adjust beam angle and intensity also lets the lighting be matched to windsock size and site conditions, ensuring the sock stays clearly readable from the air or the runway threshold, which is the entire purpose of illuminating it in the first place.

Used at a wide range of airfields, heliports, and military installations where windsock illumination is required. Particularly common at larger airports, military airbases, and facilities where maintenance access is a priority. The external illumination design is also preferred in environments where the windsock mast is too small to accommodate internal lighting, or where existing floodlight infrastructure can be repurposed. It is also used at temporary and remote airfields where simplicity and ease of maintenance are critical.

Floodlights are mounted on a ground-level pole or bracket set back from the base of the windsock mast, angled upward so the beam washes the full length of the sock without glaring toward an approaching aircraft. Fixture spacing and aiming are set during commissioning so the sock remains evenly lit from tail to throat regardless of wind direction, since the sock itself rotates freely on the mast head. Power cabling runs underground in duct from the floodlight bases back to the local distribution point, with the fixtures wired on their own circuit (often via a photocell or timer) so illumination can be verified and maintained independently of the mast structure itself. Because the light source sits at ground level, the mounting position is also chosen for straightforward access, so lamp replacement and aiming checks can be carried out without climbing the mast.

The externally illuminated windsock uses one or more floodlights mounted on the mast or on separate poles. The floodlights are typically positioned at the base of the mast, aimed upward to illuminate the full length of the wind cone. Some installations use multiple floodlights arranged around the mast to ensure even illumination from all sides. The light source is usually a high‑intensity LED floodlight with a wide beam angle (60°–120°) to cover the entire windsock. A photocell or timer controls the on/off cycle. The floodlights are housed in weatherproof enclosures (IP66/IP67) with corrosion‑resistant materials. The windsock itself is made from opaque, UV‑resistant fabric (orange and white bands) that reflects the external light, making it clearly visible at night. The external design allows for easy lamp replacement, cleaning, and adjustment of the light beam.

Unlike runway and taxiway edge lights, windsock floodlights are not part of the constant current series circuit — they are standard AC fixtures wired in parallel on their own dedicated lighting circuit, switched as a group by a photocell (or timer) rather than stepped through CCR current levels. This keeps the control logic simple by design: there is no intensity-step selection tied to visibility category, no series-loop fault monitoring, and no isolating transformer in the circuit, because the windsock is a wind-direction reference rather than a category-dependent visual aid. The photocell typically drives a contactor that energises the whole floodlight group at dusk and de-energises it at dawn, with a manual override at the local distribution point for maintenance or testing; where the site has an ALCMS, the circuit's on/off state is commonly wired back as a simple status point so a failed photocell or tripped breaker shows up as a fault, but the floodlights themselves remain outside the CCR-controlled visual aid system.

This configuration pairs a standard fabric wind cone assembly with one or more floodlight fixtures mounted separately from the cone itself, either on brackets fixed to the mast below the swivel point or on dedicated poles positioned around the base. The floodlight housings are weatherproof, corrosion-resistant enclosures rated to IP66/IP67, with a hardened glass or polycarbonate lens sealed against moisture and a mounting yoke that allows the beam angle to be adjusted so the full length of the cone is evenly lit without excessive spill or glare toward approaching aircraft. Because the light source sits outside the cone and mast, wiring runs from the floodlight housing down to a ground-level junction box are kept separate from the mast's internal cabling, simplifying lamp replacement and maintenance access without requiring work at height. The cone itself follows standard wind cone construction — UV-stabilised, flame-retardant polyester fabric on a ring-supported throat — while the mast is a conventional galvanized steel, aluminium, or fibreglass pole without the need for internal illumination wiring or a translucent fabric specification.