HIGHLIGHT: Integration of real-time in situ turbulence reports into airline flight operations

Commercial and general aviation aircraft frequently encounter unexpected atmospheric turbulence. Though rarely fatal, these encounters sometimes result in serious injuries to aircraft occupants or rerouting of flights. The cost to air carriers of these injuries (medical attention and lawsuits), equipment damage and maintenance/inspection, or rerouting is substantial. Moreover, rerouting of flights due to reported or forecast turbulence can significantly reduce the capacity of the National Airspace System (NAS). In addition, the greater the length of time a flight remains off optimal altitude, the greater the associated fuel burn with costs to both the environment and the airline industry.

Historically, turbulence has been reported by flight crews through verbal pilot reports (PIREPS). However, PIREPS are subjective, sporadic, and not always timely or geographically accurate. Because of this subjectivity, turbulence is often over-reported, resulting in pilots avoiding large blocks of airspace that may in reality be perfectly safe, considerably impacting airspace capacity, and increasing costs to the airline industry, the environment, and NAS operations.

To help address these problems, the National Center for Atmospheric Research (NCAR), under funding from the Federal Aviation Administration's (FAA) Aviation Weather Research Program (AWRP), developed an objective means of measuring atmospheric turbulence. The resultant algorithm, Eddy Dissipation Rate, or EDR, resides on the avionics system of aircraft and uses measurements from existing sensors (either accelerometers or wind sensors) to derive an measure of the turbulent state of the atmosphere. It is aircraft-independent and reported at a much greater frequency than PIREPS. In September 2008, Delta Air Lines (DAL) completed installation of the EDR turbulence detection algorithm on its fleet of approximately 80 Boeing 737-700/800's. Subsequently, the FAA and DAL conducted a year and a half long EDR Proof of Concept demonstration at the DAL Operations Control Center (OCC) in Atlanta in order to verify and document improvements to airline operations. Dispatchers had access to the EDR data as well as the Graphical Turbulence Guidance (GTG) forecast product via Experimental Aviation Digital Data Service (ADDS), and integrated the information into their strategic route planning as well as tactical real-time rerouting for aircrews in flight. The Demo provided compelling evidence that DAL dispatchers made better decisions based on improved data in order to save fuel, reduce emissions, improve safety, and positively impact NAS capacity.

In addition, the National Oceanographic and Atmospheric Administration's (NOAA) National Weather Service (NWS) Center Weather Service Unit (CWSU) at the FAA's Atlanta Air Route Traffic Control Center (ARTCC/ZTL) participated in the Demo as a first step in introducing the EDR data to air traffic management personnel. CWSU forecasters used the EDR reports as an additional data source for the routine forecasts they provide to the Traffic Management Unit (TMU), Area Supervisors, Operations Managers, Airport Traffic Control Towers (ATCTs), and Terminal Radar Approach Controls (TRACONs).

An on-going follow-on effort, the Weather Technology in the Cockpit Turbulence/Eddy Dissipation Rate (EDR) Uplink Demonstration, is assessing the feasibility of using a low-cost device for the display of turbulence forecasts and EDR information in the cockpit for direct use by the DAL flight crews. This effort will provide a Capacity and Efficiency Benefits Quantification of the use of the turbulence data in the flight deck in order to understand how the provision of turbulence observations and forecasts to the cockpit for direct use by flight crews affects flight operations and safety, efficiency, and capacity within the NAS. This presentation will review the first DAL EDR Demo procedures and results, and provide an overview and status update of the EDR Uplink Demo.