FX852S Inset Stopbar Light

The FX852S (FAA designation L-852S(L)) is an inset LED stopbar light that marks the mandatory hold-short point where a taxiway meets an active runway. It emits a high-intensity bidirectional or unidirectional red signal that is visible to flight crews across the full range of CAT II/III visibility minima, making it one of the critical defences against runway incursion events.

The fixture protrudes only 4.0 mm above the taxiway surface, meeting both FAA Style 3 and ICAO Style 4 flush-fitting requirements. Installation uses the standard 8-inch IEC seating pot or a 12-inch pot with adapter ring — the same baseplate used across ATG's FX852 taxiway family, simplifying spares inventory. An FAA L823 Style 1 water-tight connector, with an optional additional power lead, connects the fitting into the 6.6 A series circuit.

Stopbar systems impose particular demands on reliability: a failed unit that presents a clear path when a runway is active creates direct safety exposure. The FX852S addresses this with optional fail-open monitoring, reporting LED array degradation to the control room before a lamp failure becomes operationally invisible. Its fully dimmable LED array follows the tungsten halogen response curve per FAA Engineering Brief 67, so stopbar step intensities remain calibrated correctly on existing CCR infrastructure.

The -55 °C to +55 °C operating envelope accommodates the extreme diurnal temperature swings found at Gulf airports, and the IP67-rated housing resists ingress from water and airfield contaminants. The absence of a negative slope on the lens face prevents sand and pooled water from accumulating in the aperture.