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Turbulence

 Clear-air turbulence is hazardous to passengers, crew, and aircraft, and is the number one cause of injuries in non-fatal plane accidents. Unexpected encounters with severe turbulence can cause injury and sometimes death to those on board, as well as structural damage to the aircraft. Avoidance of light and moderate turbulence results in a more comfortable ride. Current forecast products give a broad view in time and space. Large regions that potentially contain turbulence are overwarned. Forecasts are made every 6 hours, and updates are triggered by pilot reports of significant turbulence; however, pilot reports are few, subjective, and sometimes ambiguous with respect to location and time of event.

Research sponsored by the FAA's Aviation Weather Research Program (AWRP) is investigating new methods of detecting turbulence, developing better algorithms and systems for 1 to 9 hour forecasts of turbulence, and establishing innovative techniques for disseminating these products.

The AWRP has developed an on-board (in-situ) algorithm which has been approved by ICAO as an international standard and integrated into the ACMS software of commercial aircraft. This algorithm provides objective turbulence measurements, which will be downlinked for use by forecasters at the AWC and will also be used for AWRP research into enhanced forecasting models. This algorithm has been installed on several United Airlines 737's and 757's and is undergoing validation and verification. Once this is complete, the algorithm will be installed on additional airframes and airlines to provide a broad automated turbulence reporting capability.

Map of the US showing turbulence observations

Detailed maps of turbulence in three dimensions are necessary for strategic and tactical route planning. Frequent updates to these forecasts permit refinement of the flight route as the weather evolves. The PDT approach is the development of the Integrated Turbulence Forecast Algorithm (ITFA), an infrastructure for automatically and continuously receiving observational and forecast weather data, as well as remote sensing and in-situ data, and then diagnosing this data to produce turbulence forecasts.

In addition to the above efforts, AWRP is engaged in a separate wind shear project associated with mountain-induced turbulence at Juneau, Alaska. Techniques being developed there are intended to enhance aviation safety in the region of the Juneau Airport by providing real-time wind information from anemometers and wind profilers at strategic locations. This information is being provided to the FAA, the National Weather Service (NWS), commercial airlines, and general aviation users.

Results of the PDT research can be accessed via the ADDS web page: http://adds.awc-kc.noaa.gov/

Benefits to the aviation community

  • Smoother ride and decreased exposure to potential injury for passengers and crew
  • Fewer hazardous encounters that are likely to cause damage to aircraft
  • More timely strategic and tactical products
  • More efficient use of national airspace

Below are the links to sub articles on Aviation Digital Data Service:

Ceiling and Visibility
Turbulence
Convective Weather
Winter Weather Research
In-Flight Icing
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