When is a missed approach required for an aircraft?

A missed approach is required when the aircraft is not continually in a position for normal descent and landing. This situation can occur due to several factors, such as poor visibility, changes in weather conditions, or misalignment with the runway approach path. The missed approach procedure is crucial because it ensures the safety of the flight; if the conditions do not allow for a safe landing, executing a missed approach allows the flight crew to climb away from the runway environment while assessing the situation, determining an alternative approach, or preparing for a different landing attempt.

Other scenarios like turbulence or emergency landings might warrant changes to the flight's operation or approach but do not specifically dictate the need for a missed approach procedure. A stable altitude might suggest that the aircraft is maintaining a safe position, but it does not necessarily correlate with the conditions required for a successful landing. The essence of a missed approach lies in the inability to continue with the landing due to a compromised approach path.