For TDZ RVR to be effective, what equipment must be present?

For Terminal Decision Zone (TDZ) Runway Visual Range (RVR) to be effective, the presence of an approach lighting system is crucial. Specifically, either an ALSF (Approach Light System with Sequenced Flashing Lights) 1 or 2, paired with High-Intensity Runway Lights (HIRL) and TDZL (Touchdown Zone Lights), provides critical visual reference points for pilots during an approach, especially in low visibility conditions.

The ALSF serves to enhance the pilot's ability to see the runway environment while also helping to properly guide the aircraft to the runway. The combination of these lighting systems creates a more effective visual approach and landing environment, making them essential for TDZ RVR operations. This means the equipment listed is tailored to ensure that visual cues are maximized, allowing pilots to make informed landing decisions during challenging visibility scenarios.