During an approach, what is the critical factor for decision making near DA/MDA?

The critical factor for decision making near Decision Altitude (DA) or Minimum Descent Altitude (MDA) during an approach is flight visibility from the cockpit. This visibility directly influences the pilot's ability to discern the runway environment and make a safe landing. If the visibility is insufficient, a pilot may not be able to see the runway or make a timely decision to execute a missed approach, which is essential for safety.

Flight visibility encompasses not just how far forward a pilot can see, but also includes the ability to identify visual cues that indicate a safe approach and landing. It is important for pilots to maintain situational awareness and ensure they can perceive the flight path and surroundings adequately, especially as they approach critical phases of landing.

Other factors, such as cloud ceiling, time to landing, and distance from the airport, may indeed affect the decision-making process in an approach, but flight visibility is the most immediate and critical factor at DA/MDA. Without sufficient visibility, the pilot cannot reliably identify whether it is safe to continue the landing or if a go-around is necessary.