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Wind Shear Detection Services (WSDS)

Wind Shear Detection Services (WSDS) is a portfolio of ground-based wind shear detection systems in the terminal environment that provide alerts and warnings of hazardous wind shear to air traffic controllers. We deploy WSDS at commercial airports because they increase aviation safety by accurately and timely detecting hazardous weather conditions.

Benefits

The benefits of WSDS include real-time detection of wind shear, microbursts, gust fronts, and wind shifts. Another benefit is prediction of wind changes, which improves aircraft efficiency when they make runway changes. WSDS projects contribute significantly to the overall safety of the National Airspace System (NAS) by preventing wind shear-related aircraft accidents.

Legacy Wind Shear Detection Systems

The WSDS portfolio sustains legacy wind shear services by resolving issues with obsolete and unsupportable parts.

We currently deploy the following legacy ground-based wind shear detection systems in the NAS:

  • Weather Systems Processor
  • Low Level Wind Shear Alert System
  • Wind Measuring Equipment

These systems provide wind shear detection to over one hundred airports and collect data to

  • NAS subsystems Integrated Terminal Weather System
  • Corridor Integrated Weather System
  • Airport Surveillance Radar 9 (ASR-9)
  • Automated Surface Observing System
  • Terminal Weather Information for Pilots
  • Data displays in Air Traffic Control Towers (ATCT) and Terminal Radar Approach Control (TRACON)

Low Level Wind Shear Alert System (LLWAS) and Wind Measuring Equipment (WME)

In 1977, LLWAS was originally developed in response to the fatal 1975 Eastern Air Lines Flight 66 accident, reportedly caused by wind shear. LLWAS is a ground-based system that detects wind shear on and around the runway to prevent aircraft accidents during take-off and landing.

LLWAS uses pole-mounted wind sensors to obtain wind speed and direction data. Then, radio frequency (RF) communications transmit this data to a master station inside the facility. Using weather algorithms, the master station analyzes the data to determine whether hazardous wind shear, such as microburst and gust fronts, is present. If present, the master station generates alerts to transmit to ATCT and TRACON facilities and display on Ribbon Display Terminals. Air traffic controllers pass the data to pilots to prevent wind shear encounters.

Weather Systems Processor (WSP)

The Weather Systems Processor (WSP) was originally developed in the 1990s in response to the fatal 1985 Delta Airlines Flight 191 accident at Dallas Fort Worth International Airport, caused by wind shear. Initially, 45 TDWRs were purchased and installed at major airports. Although 105 TDWRs were planned, because of funding issues, a WSP was added to the ASR-9 at 34 locations having wind shear events.

The WSP works with the ASR-9 at the RF level with minimal ASR-9 changes and contains its own receiver and signal processing hardware. The WSP computer processes resulting velocity and precipitation data using similar algorithms in TDWR for microburst, gust front, and wind shear detection. A graphical image is generated for displays at ATCT and TRACON facilities. Numerical wind shear alerts are also generated on the controllers' Ribbon Display. The controllers pass on this data to pilots to prevent wind shear encounters.

Current Status

WSDS contains two Work Packages (WP). WP 1 sustains legacy wind shear service while WP2 will explore new wind shear requirements and introduce equipment to unprotected and under-protected areas.

WSDS WP1 is currently in progress and will resolve issues of obsolete and unsupportable parts, which plague wind shear detection systems such as WSP, LLWAS, and WME. It includes a Service Life Extension Program and Technical Refresh to replace parts based on form, fit, and function. WP1 will resolve several safety and performance-related issues and make WSP, LLWAS, and WME comply with National Telecommunication Information Administration and International Civil Aviation Organization requirements. To date, the systems within WSDS WP1 prove their benefit. The task within WSDS WP1 enables the continued detection of hazardous wind shear in the terminal environment and the prevention of wind shear related accidents.

WP2 is a portfolio program for new and legacy wind shear detection systems. It will introduce Wind Hazard Detection Equipment (WHDE) that will detect dry wind shear phenomenon in the terminal environment and prevent aircraft accidents during take-off and landing. This system also complements the conventional RF-based radars, for example TDWR and WSP, by detecting dry wind shear events in dry weather climates. WHDE will provide hazardous wind shear alerts and warnings to air traffic controllers who will pass the information to pilots to avoid potential wind shear encounters and increase safety for the flying public. To date, the timeline for WSDS WP2 is still under discussion.

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This page was originally published at: https://www.faa.gov/air_traffic/weather/wsds/

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