An Update on the FAA

1
An Update on the FAAs EDR Reporting Program

• Larry Cornman
• National Center for
• Atmospheric Research

2
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.

3
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

4
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?

5
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.

6
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.

7
EDR vs. RMS-g?

• Given knowledge of aircraft type, airspeed,
  altitude and weight, EDR can be converted into
  RMS-g with sufficient accuracy.

8
Conversion Between EDR and RMS-g Illustrated
with Data from NASA B-757 Aircraft
2407 one-minute samples
Measured RMS-g
Median
median r0.94 m0.98
EDR-predicted RMS-g
peak r0.95 m1.03
Peak
9
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.

10
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
11
EDR on Experimental ADDS

• Display contains EDR reports, pireps, GTG.
• Movie loops, cross-sections, etc

12
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
13
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
14
Future Airline Participation

• Discussions ongoing with Delta Airlines.
• Discussions begun with Northwest Airlines.
• Future work is contingent on continued FAA
  funding

15
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?)

16
Other Issues, contd

• 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.