What is required visibility for consideration of descent from the MDA?

For an approach to continue below the Minimum Descent Altitude (MDA), the visibility requirement includes having the runway environment in sight. The term "runway environment" refers to visual references that allow the pilot to conduct a safe descent and landing, which typically includes seeing the runway itself, its markings, or other prominent features related to the runway.

Meeting this criterion is critical because it ensures that a pilot has enough visual references to navigate safely and confirm the landing trajectory. Once the runway environment is visible, the pilot can confidently initiate descent from MDA, provided other operational conditions are also satisfied.

The other options do exist as important considerations, but they do not directly dictate the immediate criteria for initiating descent from the MDA like the visibility of the runway environment does. Thus, visual contact with the runway is paramount for safe approach and landing decisions.