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 is a part of the Weather Sensors Portfolio (WSP), which consolidates, prioritizes and manages sustainment activities for the weather sensors programs.

WSDS Sustainment 2 is currently in progress and will replace obsolescent weather sensors, processors and software. It provides a nationwide technical refresh effort to keep legacy windshear detection systems working after they exceed their planned 20-year service lives.  This program will address all obsolescence and supportability problems of the Low-Level Windshear Alert Systems and Weather Systems Processors.

As these systems automatically detect hazardous microbursts and wind shear activity near runways and along approach/departure corridors, sustainment of these systems will allow Air Traffic Controllers to continue providing warnings to aircraft of hazardous wind shear and microburst conditions as they happen.