Comparisons of Operational Eddy Dissipation Rate (EDR) Derivations from Multiple Platforms

The Eddy Dissipation Rate (EDR) algorithm for in-situ reported aircraft turbulence was developed by the National Center for Atmospheric Research (NCAR) and operationalized by the Federal Aviation Administration (FAA) as part of the continuing efforts to mitigate injuries from these phenomena and was designated by the International Civil Aviation Organization (ICAO) as the official reporting metric for turbulence. In the United States alone, there are now nearly 50,000 EDR reports daily from over 13,000 aircraft. These EDR measurements and reports are widely used throughout industry today to help avoid turbulence encounters in flight. As many new aircraft have become equipped to support EDR measurements, new algorithms from industry are demonstrating alternative, viable methods for measuring turbulence encounters and each may be employed by airlines to mitigate turbulence encounters. Many of these new algorithms are not based on input from the aircraft and are instead derived from other sources such as personal electronic devices in the cockpit. The integration of these new algorithms into the commercial airline market has created new gaps among operational users and regulatory authorities attempting to improve flight safety regulations. To address this gap, The MITRE Corporation is supporting the FAA to better understand and quantify the differences in these disparate EDR / turbulence assessments. Initial work highlighted the strengths and weaknesses in performing NAS-wide correlation efforts. Specifically, findings revealed some commonalities, in space and time, of turbulence observations, but also revealed numerous complexities inhibiting effective comparison, considering the sparsity of turbulence in the atmosphere.

Building on the previous effort, working with industry data users and providers, larger samples of EDR observations were obtained and evaluated against each other in a real-world sampling scenario, accounting for time and space constraints, using avionics-derived EDR output as the baseline observation. Accounting for time and space boundaries, across multiple altitudes and EDR intensity ranges, bounds of intercomparison uncertainty were determined and tested. The alternative method employed with this effort shows results to be within an acceptable margin of error. Results from this work will support efforts from the Radio Technical Committee for Aeronautics (RTCA) Special Committees with an emphasis on aviation related turbulence and to help satisfy turbulence safety requirements prescribed by the U.S. National Transportation Safety Board (NTSB).

NOTICE

This work was produced for the U.S. Government under Contract 693KA8-22-C-00001 and is subject to Federal Aviation Administration Acquisition Management System Clause 3.5-13, Rights In Data-General, Alt. III and Alt. IV (Oct. 1996).

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