What condition triggers the Capacity type of Irregular Operation?

The Capacity type of Irregular Operation is triggered when all gates at an airport become occupied due to full passenger capacity. This scenario indicates that the airport is unable to accommodate additional arriving aircraft because the existing gates are fully utilized. It illustrates a situation where the physical infrastructure can no longer support the traffic demand, causing a backlog of aircraft that may need to hold or divert, thereby creating irregular operations. This condition typically signifies a failure to manage the flow of both arriving and departing aircraft in a manner that maintains efficiency and safety, leading to lengthy delays and operational challenges.

In this context, while other conditions such as irregular landing times, stranded passengers, and weather delays can also lead to disruptions in airport operations, they are not specific to the issue of gate occupancy directly impacting capacity. The focus on gate occupancy in this particular choice makes it the correct answer, as it directly relates to the definition of capacity constraints in the operational context of an airport.