What happens when a pilot sees dark amber in a tri-color VASI?

In a tri-color VASI system, the colors provide visual cues to help pilots understand their position relative to the ideal glide path during an approach to landing. When a pilot sees dark amber in a tri-color VASI, it indicates that the aircraft is descending toward the glide path but has not yet reached it. This color signifies that the aircraft is slightly below the optimal glide path, prompting the pilot to adjust their altitude by climbing to ensure they are on the correct descent trajectory for landing.

This representation of the aircraft's position allows pilots to make effective adjustments, enhancing safety and accuracy during approaches. The crucial aspect of dark amber is to communicate that there is still a need to ascend slightly to align with the glide path, differentiating it from other color interpretations in the VASI system.