Reports submitted by pilots, subjective and often very inaccurate, are the most frequently used method for trying to predict when and where turbulence will occur.

Scientists from the University of Warsaw Faculty of Physics have demonstrated that turbulence can be detected in a faster and more precise way using data already being broadcast by the aircraft. Doctoral student Jacek Kopec has extracted this information from the flight parameters routinely broadcast by the transponders installed in most modern commercial airplanes.

Turbulence reports submitted by pilots are subjective and often very inaccurate. Image credit: Pixabay. “Unfortunately, there is no access to materials regarding vertical accelerations. That was why we decided to check if we could extract such data from other flight parameters, accessible in Mode-S and ADS-B transmissions," Kopec notes.

Kopec and colleagues from the Faculty of Physics tested three algorithms of turbulence detection. The first relied on information about the position of aircraft (ADS-B transmissions). However, preliminary tests and their comparison against the parameters registered in the same area by research aircraft failed to produce satisfactory results.

Each of the remaining two algorithms used the parameters received approximately every four seconds through Mode-S transmissions. In one approach, the parameters were analyzed using the standard theory of turbulence. In the other approach, the scientists adapted a method for determining turbulence intensity previously used to measure air disturbances on a very small scale in the understory of forests.

The researchers found that once wind velocity in the vicinity of an aircraft was determined and its changes were analyzed in successive readings, it was possible to use the latter two theoretical approaches to locate turbulence areas at a range of 20 km. Passenger aircraft need around 100 seconds to travel this distance, so this level of accuracy should allow pilots sufficient time to maneuver their airplane so as to effectively avoid turbulence.

In order to be operational, the system needs only software and a computer connected to the devices that receive Mode-S transmissions from the transponders onboard aircraft. Such devices are standard equipment in air traffic control institutions in Europe. In this setup, passenger aircraft act as sensors by creating a dense network of measurement points above the continent.