What determines whether a missed approach should be initiated?

The decision to initiate a missed approach is fundamentally driven by missed approach criteria, which are specifically designed to provide clear guidelines for pilots in situations where landing cannot be safely accomplished. These criteria encompass factors such as decision height (DH) or minimum descent altitude (MDA), visibility requirements, and the aircraft's position relative to the runway.

If the aircraft does not meet these delineated criteria during the final approach phase—such as failing to visually acquire the runway or being unable to maintain the required descent profile—a missed approach must be executed to ensure safety. These criteria are closely tied to standard operating procedures and regulations, providing a structured and predictable framework within which pilots operate.

While other considerations like visibility conditions, air traffic control instructions, and aircraft performance metrics play important roles in flight operations, the specific trigger for commencing a missed approach rests on whether the established missed approach criteria have been satisfied or not.