In response to a series of commercial aircraft accidents in the 1970s and 1980s, the U.S. Federal Aviation Agency deployed three ground-based low altitude wind shear detection systems: the Low Altitude Wind Shear Alert System (LLWAS), the Terminal Doppler Weather Radar (TDWR) and the Airport Surveillance Radar Weather Systems Processor (ASR-9 WSP). Today's near-zero wind-shear accident rate seems to confirm the safety benefits provided by these systems. In addition, the broad area measurement capability of TDWR and WSP provides ancillary delay reduction benefits, for example by forecasting airport wind shifts which may require runway reconfiguration.

The current deployment strategy for these various wind shear detection systems is justified by a 1994 Integrated Wind Shear Systems Cost Benefit Analysis conducted for the FAA. In this report, we update the technical and operational assumptions used in that analysis in view of NAS evolution since 1994. In particular we utilize improved models for inter comparing wind shear system performance, consider the impacts of pilot training and on-board Predictive Wind Shear detection systems, and a broader set of delay-reduction benefits than were considered in the 1994 study. This evaluation provides insight into airport weather observation needs supporting the Next Generation Air Transportation System.

This work was sponsored by the Federal Aviation Administration under Air Force Contract No. FA8721-05-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the United States Government.