Which situation does NOT trigger a missed approach requirement?

The correct answer is that having visibility over the threshold does not trigger a missed approach requirement. In aviation, a missed approach is required when certain safety conditions are not met, and visibility is a critical factor in that assessment. If visibility is above the minimum requirements established for the approach, pilots are typically able to continue their descent safely and may not need to execute a missed approach.

Other triggers for a missed approach, such as not being stabilized, experiencing equipment malfunctions, or observing full-scale deflection on instruments, indicate a significant deterioration in the pilot's ability to safely land the aircraft. These conditions suggest that the pilot must discontinue the approach to re-evaluate the situation, whereas good visibility implies a higher likelihood of successfully completing the landing. Thus, the presence of adequate visibility is not a reason to initiate a missed approach, making it the correct choice in this scenario.