The airborne wind shear detection and alert system, fitted in an

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...

, detects and alerts the pilot both visually and aurally of a

wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal ...

condition. A reactive wind shear detection system is activated by the aircraft flying into an area with a wind shear condition of sufficient force to pose a hazard to the aircraft. A predictive wind shear detection system is activated by the presence of a wind shear condition ahead of the aircraft. In 1988, the U.S.

Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...

(FAA) mandated that all turbine-powered commercial aircraft must have on-board wind shear detection systems by 1993. Airlines successfully lobbied to have commercial turbo-prop aircraft exempted from this requirement. In the predictive wind shear detection mode, the weather radar processor of the aircraft detects the presence of a microburst, a type of vertical wind shear condition, by detecting the Doppler frequency shift of the microwave pulses caused by the microburst ahead of the aircraft, and displays the area where it is present in the Navigation Display Unit (of the Electronic Flight Instrument System) along with an aural warning.

History of development

In June 1975,

Eastern Air Lines Flight 66 Eastern Air Lines Flight 66 was a regularly scheduled flight from New Orleans to New York City that crashed on June 24, 1975 while on approach to New York's John F. Kennedy International Airport, killing 113 of the 124 people on board. The cras ...

crashed on approach to New York JFK Airport due to microburst-induced wind shear. Then, in July 1982,

Pan Am Flight 759 Pan Am Flight 759 was a regularly scheduled domestic passenger flight from Miami to San Diego, with en route stops in New Orleans and Las Vegas. On July 9, 1982, the Boeing 727 flying this route crashed in the New Orleans suburb of Kenner after ...

crashed on takeoff from New Orleans International Airport in similar weather conditions. Finally, in August 1985, wind shear and inadequate reactions by the pilots caused the crash of

Delta Air Lines Flight 191 Delta Air Lines Flight 191 was a regularly scheduled Delta Air Lines domestic service from Fort Lauderdale, Florida, to Los Angeles with an intermediate stop at Dallas/Fort Worth International Airport (DFW). On August 2, 1985, the Lockhee ...

on approach to Dallas/Fort Worth International Airport in a thunderstorm. On July 24, 1986, the FAA of United States and NASA signed a memorandum of agreement to formally begin the Airborne Wind-Shear Detection and Avoidance Program (AWDAP). As a result, a wind-shear program was established in the Flight Systems Directorate of NASA's Langley Research Center. After five years of intensely studying various weather phenomena and sensor technologies, the researchers decided to validate their findings in actual flight conditions. They chose an extensively modified Boeing 737, which was equipped with a rear research cockpit in place of the forward section of the passenger cabin. A modified Rockwell Collins model 708 X-band ground-based radar unit was used in the AWDAP experiments. The real-time radar processor system used during 1992 flight experiments was a VME bus-based system with a Motorola 68030 host processor and three DSP boards. On September 1, 1994, the weather radar model RDR-4B of the Allied-Signal/Bendix (now Honeywell) became the first predictive wind-shear system to be certified for commercial airline operation. In the same year, Continental Airlines became the first commercial carrier to install an airborne predictive wind-shear detection system on its aircraft. By June 1996, Rockwell Collins and Westinghouse's Defense and Electronics Group (now Grumman/Martin) also came up with FAA-certified predictive wind-shear detection systems. The

IEEE Intelligent Transportation Systems Society The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...

is conducting research for further development of this system.

References

{{DEFAULTSORT:Airborne Wind Shear Detection And Alert System Avionics Aircraft instruments Warning systems

History of development

See also

References