COLOGNE, Germany - German Aerospace Center (DLR) researchers have conducted flight tests using live commercial air traffic data to evaluate a wake vortex warning system designed to improve pilot awareness of potentially hazardous turbulence behind aircraft.
Wake vortices, also known as wake turbulence, are rotating air currents that form behind aircraft as they generate lift. These vortices typically appear as two counter-rotating airflows that slowly descend behind the aircraft. When produced by large aircraft, the vortices can contain significant energy and pose hazards to trailing aircraft.
"Flying into a wake vortex can trigger a sudden, severe reaction in an aircraft that encounters it," said André Koloschin of the DLR Institute of Flight Systems. "This is largely avoided through procedures and safety distances. However, previous studies have shown that an additional warning system could further enhance pilots' situational awareness."
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Vortex behavior
The research focuses on the Wake Encounter Avoidance and Advisory (WEAA) system, which is under development at DLR to predict and warn pilots about potential wake vortex encounters. The system uses models developed by the DLR Institute of Atmospheric Physics to forecast vortex behavior, including predicted movement and intensity.
"The challenge is to generate sufficiently accurate vortex predictions based on available meteorological data from various sources," said Frank Holzäpfel, an atmospheric physicist involved in the project.
In addition to weather data, the system incorporates information from aircraft and surrounding air traffic to identify possible conflicts and present avoidance options.
To evaluate the accuracy of the vortex prediction models, researchers needed precise information about the actual location of wake vortices. During the tests, DLR flew its ISTAR (In-Flight Systems and Technologies Airborne Research) aircraft directly into the vortices and recorded detailed aircraft performance data.
Researchers were able to safely perform these maneuvers when the vortices were visible, which occurs when contrails form and are drawn into the rotating airflows. Test flights were therefore conducted under atmospheric conditions that favor contrail formation.
The testing campaign required coordination among air traffic control, the ISTAR research aircraft, and nearby commercial aircraft to ensure safe operations.
Across five test flights, researchers conducted 120 vortex encounters, producing a large dataset for further analysis and refinement of the prediction models.
"Using the current version of our prediction model, we were able to carry out an initial assessment in real time during the flights," Koloschin said. "Qualitatively, all predictions met expectations. The next step is to systematically analyze the data quantitatively, which will allow the technology to be further developed towards practical application."
