What is required for descent below MDA?

To safely descend below Minimum Descent Altitude (MDA), it is essential to have a visual reference with the runway environment. This requirement is rooted in ensuring that a pilot has sufficient visibility and can positively identify the runway or approach lights before proceeding with the descent. The visual reference is crucial for the pilot to maintain control of the aircraft as they approach landing, ensuring they can navigate safely to the runway without relying solely on instruments.

Having visual contact allows the pilot to confirm that they are on the correct flight path and that the runway is suitable for landing. This practice significantly reduces the risk of controlled flight into terrain or flying below safe altitudes without visual verification of the landing conditions. The other options do not directly address the necessary condition required for a descent below MDA.