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LLWAS
A low-level windshear alert system (LLWAS) measures average surface wind speed and direction using a network of remote sensor stations, situated near runways and along approach or departure corridors at an airport. Wind shear is the generic term for wind differences over an operationally short distance (in relation to flight) which encompass meteorological phenomena including gust fronts, microbursts, vertical shear, and derechos. Background LLWAS compares results over its operating area to determine whether calm, steady winds, wind shifts (in relation to runways), wind gusts, divergent winds, sustained divergent winds (indicative of shear), or strong and sustained divergent winds (indicative of microbursts) are observed. A LLWAS master station polls each remote station every system cycle (nominally every ten seconds) and provides prevailing airport wind averages, runway specific winds, gusts, may set new wind shear alerts or microburst alerts and reset countdown timers of elapse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LLWAS
A low-level windshear alert system (LLWAS) measures average surface wind speed and direction using a network of remote sensor stations, situated near runways and along approach or departure corridors at an airport. Wind shear is the generic term for wind differences over an operationally short distance (in relation to flight) which encompass meteorological phenomena including gust fronts, microbursts, vertical shear, and derechos. Background LLWAS compares results over its operating area to determine whether calm, steady winds, wind shifts (in relation to runways), wind gusts, divergent winds, sustained divergent winds (indicative of shear), or strong and sustained divergent winds (indicative of microbursts) are observed. A LLWAS master station polls each remote station every system cycle (nominally every ten seconds) and provides prevailing airport wind averages, runway specific winds, gusts, may set new wind shear alerts or microburst alerts and reset countdown timers of elapse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NEXRAD
NEXRAD or Nexrad (Next-Generation Radar) is a network of 160 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce, the Federal Aviation Administration (FAA) within the Department of Transportation, and the U.S. Air Force within the Department of Defense. Its technical name is WSR-88D (''Weather Surveillance Radar, 1988, Doppler''). NEXRAD detects precipitation and atmospheric movement or wind. It returns data which when processed can be displayed in a mosaic map which shows patterns of precipitation and its movement. The radar system operates in two basic modes, selectable by the operator – a slow-scanning ''clear-air mode'' for analyzing air movements when there is little or no activity in the area, and a ''precipitation mode'', with a faster scan for tracking active weather. NEXRAD has an increased emphasis on autom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Runway Safety
Runway safety is concerned with reducing harm that could occur on an aircraft runway. Safety means avoiding incorrect presence (incursion) of aircraft, inappropriate exits (excursion) and use of the wrong runway due to confusion. The runway condition is a runway's current status due to meteorological conditions and air safety. Definitions of runway accidents Several terms fall under the flight safety topic of runway safety, including incursion, excursion, and confusion. Terms such as runway event or runway accident are used for such incidents. Runway incursion Runway incursion involves an aircraft, and a second aircraft, vehicle, or person. It is defined by ICAO and the U.S. FAA as "Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take off of aircraft." [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remote Sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth and other planets. Remote sensing is used in numerous fields, including geography, land surveying and most Earth science disciplines (e.g. hydrology, ecology, meteorology, oceanography, glaciology, geology); it also has military, intelligence, commercial, economic, planning, and humanitarian applications, among others. In current usage, the term ''remote sensing'' generally refers to the use of satellite- or aircraft-based sensor technologies to detect and classify objects on Earth. It includes the surface and the atmosphere and oceans, based on propagated signals (e.g. electromagnetic radiation). It may be split into "active" remote sensing (when a signal is emitted by a satellite or aircraft to the object and its reflection detected by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 crash was determined to be caused by wind shear caused by a microburst, but the failure of the airport and the flight crew to recognize the severe weather hazard was also a contributing factor. Flight information Eastern Air Lines Flight 66 was a regularly scheduled passenger flight from New Orleans, Louisiana's New Orleans International Airport (renamed in 2001 to Louis Armstrong New Orleans International Airport) to John F. Kennedy International Airport in Jamaica, Queens, New York. On Tuesday June 24, 1975, Flight 66 was operated using a Boeing 727 trijet, registration number ''N8845E''. The flight departed from Moisant Field at 13:19 Eastern Daylight Time with 124 people on board, including 116 passengers and 8 crew. The flight opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorological Instrumentation And Equipment
Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not begin until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at Weather prediction, prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics, and more particularly in the latter half of the 20th century the development of the computer (allowing for the automated solution of a great many modelling equations) that significant breakthroughs in weather forecasting were achieved. An important branch of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water. Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Direction
Wind direction is generally reported by the direction from which it originates. For example, a ''north'' or ''northerly'' wind blows from the north to the south. The exceptions are onshore winds (blowing onto the shore from the water) and offshore winds (blowing off the shore to the water). Wind direction is usually reported in cardinal (or compass) direction, or in degrees. Consequently, a wind blowing from the north has a wind direction referred to as 0° (360°); a wind blowing from the east has a wind direction referred to as 90°, etc. Weather forecasts typically give the direction of the wind along with its speed, for example a "northerly wind at 15 km/h" is a wind blowing ''from'' the north at a speed of 15 km/h. Measurement techniques A variety of instruments can be used to measure wind direction, such as the windsock and wind vane. Both of these instruments work by moving to minimize air resistance. The way a weather vane is pointed by prevailing winds indicates the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Weather Service Unit
A Center Weather Service Unit (CWSU) is a National Weather Service (NWS) unit located inside each of the Federal Aviation Administration's 22 Air Route Traffic Control Centers (ARTCC). Overview CWSU meteorologists provide support for FAA's air traffic management with pertinent meteorological information for airports and airspace in the control center's area of responsibility. Meteorologists disseminate information to brief air traffic control area managers where, when, and what is expected, when the weather arrives in the ARTCC's various sectors. Dissemination is by computer products, by incoming phone requests, and by stand up briefings. Occasionally CWSUs provide weather information and recommendations directly to air traffic controllers. They sometimes will provide information directly to the pilots of aircraft in distress due to hazardous weather conditions. In addition to SIGMETs (significant meteorological events), Convective SIGMETs (significant meteorological event a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airborne Wind Shear Detection And Alert System
The airborne wind shear detection and alert system, fitted in an aircraft, detects and alerts the pilot both visually and aurally of a wind shear 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 (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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USAir Flight 1016
USAir Flight 1016 was a regularly scheduled flight in the southeastern United States, between Columbia, South Carolina, and Charlotte, North Carolina. On July 2, 1994, the flight encountered heavy thunderstorms and microburst-induced windshear while attempting to land, and crashed into heavy trees and a private residence near the The crash and ensuing fire caused 37 fatalities and seriously injured Flight History of the flight On Saturday, July 2, 1994, the McDonnell Douglas DC-9, registered ''N954VJ,'' that was flying as USAir Flight 1016 departed Columbia Metropolitan Airport at 18:15 EDT for the 35-minute flight to Charlotte/Douglas International Airport. The crew consisted of Captain Michael Greenlee (38), First Officer James Phillip "Phil" Hayes (41), and three flight attendants. There were 52 passengers (including two infants) on board. The flight was uneventful until the approach to Charlotte, where several severe thunderstorms were in the vicinity of the airport. At ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Transportation Safety Board
The National Transportation Safety Board (NTSB) is an independent U.S. government investigative agency responsible for civil transportation accident investigation. In this role, the NTSB investigates and reports on aviation accidents and incidents, certain types of highway crashes, ship and marine accidents, pipeline incidents, bridge failures, and railroad accidents. The NTSB is also in charge of investigating cases of hazardous materials releases that occur during transportation. The agency is based in Washington, D.C. It has four regional offices, located in Anchorage, Alaska; Denver, Colorado; Ashburn, Virginia; and Seattle, Washington. The agency also operates a national training center at its Ashburn facility. History The origin of the NTSB was in the Air Commerce Act of 1926, which assigned the United States Department of Commerce responsibility for investigating domestic aviation accidents. Before the NTSB, the Federal Aviation Administration's (FAA; at the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Doppler Weather Radar
Terminal Doppler Weather Radar (TDWR) is a Doppler weather radar system with a three-dimensional "pencil beam" used primarily for the detection of hazardous wind shear conditions, precipitation, and winds aloft on and near major airports situated in climates with great exposure to thunderstorms in the United States. As of 2011, all were in-service with 45 operational radars, some covering multiple airports in major metropolitan locations, across the United States & Puerto Rico. Several similar weather radars have also been sold to other countries such as China (Hong Kong). Funded by the United States Federal Aviation Administration (FAA), TDWR technology was developed in the early 1990s at Lincoln Laboratory, part of the Massachusetts Institute of Technology, to assist air traffic controllers by providing real-time wind shear detection and high-resolution precipitation data. The primary advantage of TDWRs over previous weather radars is that it has a finer range resolution—me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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