Wake Vortex Avoidance versus Landing Capacity

Wake vortex separations are limiting factor in landing capacity of airports. The increasing air traffic forms the need for more flexible separation procedures taking into account the actual weather situation and the parameters of a more individual aircraft pairing. The present separation standards have to be investigated carefully with the aim to discover possible margins by improving the limiting constrains without adverse effects on safety. Separation reductions can also be achieved by wake vortex avoidance using prediction systems for the wake related hazard zones their development and movement. Avoiding these zones allows safe and undisturbed flight operations. The definition of a reliable and validated safety criterion is the fundamental element for the determination of hazard areas. The presented definition is based on the normalized required roll control power of the encountering aircraft. For manually controlled aircraft the limit of the acceptable normalized roll control power can be established using full flight simulator studies and in-flight simulations. Parameterization of the relevant parameters leads to the universally applicable concept of the "Simplified Hazard Area Prediction" method (SHAPe). SHAPe provides the hazard area dimensions for specific approach situations. SHAPe is part of a Wake Vortex Prediction and Monitoring System developed within the DLR project Wirbelschleppe II for creating safe and reduced landing separations. Some general results for specific approach conditions on a single runway are presented