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An Update on the FAA’s EDR Reporting Program. Larry Cornman National Center for Atmospheric Research. The Need for Automated Turbulence Reports. Turbulence can be a very dynamic and spatially localized phenomena – hence the need for real-time measurements.
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An Update on the FAA’s EDR Reporting Program Larry Cornman National Center for Atmospheric Research
The Need for Automated Turbulence Reports • Turbulence can be a very dynamic and spatially localized phenomena – hence the need for real-time measurements. • Pilot reports are problematic in that they are subjective measures of the aircraft response to the turbulence – not quantitative measures of the atmosphere.
In situ Turbulence Measurement and Reporting System Goal: To augment/replace subjective PIREPs with objective and precise turbulence measurements. Features: • Atmospheric turbulence metric: eddy dissipation rate (EDR). • EDR can be scaled into aircraft turbulence response metric (RMS-g). • Adopted as ICAO Standard
EDR vs. RMS-g? • EDR is a measure of the turbulent state of the atmosphere. • RMS-g is the response of a given aircraft – at a given flight condition – to the turbulence. • Both are valid quantities, the issue is what is the appropriate/best use of them?
EDR vs. RMS-g? • Reporting EDR from an aircraft requires no additional information. • Reporting RMS-g from an aircraft requires information on aircraft type, altitude, weight, and airspeed.
EDR vs. RMS-g? • Forecasters, models, scientists want EDR. • Pilots would probably want RMS-g. • ATC, Dispatch: Since they are talking to a number of users at a time, do they want aircraft specific, or aircraft independent measure? • Maintenance would want peak-g.
EDR vs. RMS-g? • Given knowledge of aircraft type, airspeed, altitude and weight, EDR can be converted into RMS-g with sufficient accuracy.
Conversion Between EDR and RMS-g: Illustrated with Data from NASA B-757 Aircraft 2407 one-minute samples Measured RMS-g Median median r=0.94 m=0.98 EDR-predicted RMS-g peak r=0.95 m=1.03 Peak
EDR vs. RMS-g? • FAA/NCAR position is: Use EDR as the reporting metric for air-ground, air-air, and ground-air. If a given user wants RMS-g, convert EDR at their location.
Increase inSpatial/temporal Coverage: UAL EDR ReportsCompared to pireps 1.3 million EDR reports/month from 100 or so aircraft - compared to 55k pireps from all aircraft. 737 757 737 + 757
EDR on Experimental ADDS • Display contains EDR reports, pireps, GTG. • Movie loops, cross-sections, etc…
Major Upcoming Activities • SWA implementation in CY06/07. • Status: preliminary software has been delivered to Honeywell, who is doing integration and testing. SWA Route Structure
GTG Status GTG1/ADDS Example • GTG1 • On “Operational ADDS” since March 2003 • CAT above FL200 • Based on RUC 13/20 • Forecasts out to 12 hrs • GTG2 • On “Experimental ADDS” since Nov 2004 • Improved turbulence diagnostics • “CAT” above FL100 • Based on RUC 13/20 • Forecasts out to 12 hrs • Textual representation • Includes UAL in situ EDR measurements above FL200 GTG2/EDR GTG2/PIREPS
Future Airline Participation • Discussions ongoing with Delta Airlines. • Discussions begun with Northwest Airlines. Future work is contingent on continued FAA funding…
Other Issues • Cost/Optimization • Since turbulence can be highly-localized and temporally dynamic, having as many measurements (even null) as possible is important. But this has to be balanced by cost considerations. • Event-based reporting is a partial, though not optimal, solution (what happened between the events?)
Other Issues, cont’d • Resolving the EDR vs. RMS-g issue and international harmonization: • ICAO standard is EDR. • TAMDAR uses EDR. • Will all US carriers use EDR? • AMDAR does not use EDR.