# Presentation: 103407

## 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

**median**
**r=0.94**
**m=0.98**

**peak**
**r=0.95**
**m=1.03**

**Conversion Between EDR and RMS-g: Illustrated with**
**Data from NASA B-757 Aircraft **

- EDR-predicted RMS-g

- Measured RMS-g

**2407 one-minute samples**

- Median

- 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 in Spatial/temporal Coverage: UAL EDR Reports Compared 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
- 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/PIREPS

- GTG2/EDR

- GTG1/ADDS Example

## 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.