Wake vortex separation standards are used to prevent hazardous wake vortex encounters. A "safe" separation model can be used to assess the safety of proposed changes in the standards. A safe separation model can be derived from an encounter hazard model and a vortex decay model. This report presents subsequent developments and applications of such a model which was first developed in the early 1980s. A static encounter model is coupled with a decay model based on sodar measurements of vortex decay. The separation standards and procedures used from 1976 to 1994 are assumed to be safe based upon the abence of IFR accidents. Various versions of the model are used to assess how aircraft should be classified and to evaluate the safety of a possible four-class aircraft separation system. Recommendations are made for ways of improving the safe separation model.
A Laser-Doppler velocimeter (LDV) was used to monitor the wake vortices shed by 5300 landing aircraft at a point 10,000 feet from the runway threshold...
The initial separation distance (bo) between a counter-rotating vortex pair generated by an aircraft is a fundamental parameter affecting wake turbule...
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United States Department of Transportation
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