Methods of Aircraft Re-categorizations for Reducing Wake Vortex Separations

The current criteria of wake vortex separation may limit the capacity of the busy airports despite ensuring flight safety. Based on plenty of measured data together with the knowledge of wake vortex behavior, the concept of Recategorization (RECAT) has been proposed by the international air traffic researchers. This concept has attracted more and more interests, as it can apply to reduce separations with more precision by increasing the amount of aircraft categories. The methods for classifying aircraft categories were studied systematically, and the parameters termed as Required Decay Distance (RDD) and Wake Vortex Impedance (WVI) were proposed by authors to consider the influence of leading aircraft’s wake vortex circulation, and the resistant ability of following aircraft when encountering wake vortex. By comparing RECAT-I with RECAT-EU, the standard we proposed called RECAT-NEW can obtain more balanced and reasonable results in safety domain. Furthermore, on the basis of the data in airport peak operation conditions, the RECAT-NEW is expected to increase 2.2% of airport capacity. Keywords-wake vortex separation standards; aircraft recategorization; required decay distance; wake vortex impedance; required actual roll rate