One contributor for excessive flight delays is insufficient ground operation performance with excessive process durations. Further productivity is measured not only by the airline but also by the airport operator and the ground handling companies. Collaborating in the A-CDM with other partners, the aim is to understand process characteristics and to predict process duration for the exact Gate Occupancy Time needed for operational capacity planning. Within this paper focus is set on process variations within specific sub processes for different airports, depending on their network function. An introduction of an intermediate airport category beside hub and non-hub airport is given. We found significant dependencies of turnaround characteristics depending on airport classification, especially for loading process on hub airports.