DEmonstration of LIdar based Clear Air Turbulence detection

Navigation Menu


Partners' access


General description

The DELICAT project is supported by the European Commission within the frame of the 7th Framework Program (FP7).

DELICAT stands for Demonstration of LIdar based Clear Air Turbulence.

Atmospheric turbulence encounters are the leading cause of injuries to passengers and flight crews in non-fatal airline accidents. A whole class of turbulence, representing 40% of turbulence accidents, and designated as Clear Air Turbulence (CAT), cannot be detected by any existing airborne equipment, including state-of-the-art weather radar; this explains that the number of turbulence accidents has been growing by a factor of 5 since 1980, 3 times faster than the increase of the air traffic.

Aircraft damaged during a Clear Air Turbulence encounter

The objective of DELICAT is to validate the concept of LIDAR based medium range turbulence detection, allowing efficient protection of the passengers and crew by actions such as seat belts fasten. The validation will be based on the comparison of the information on a turbulent atmospheric area, provided on one side by the remote LIDAR sensor and on the other side by the aircraft sensors (acceleration, air speed, temperature).

Project summary

Atmospheric turbulence encounters are the leading cause of injuries to passengers and flight crews in non-fatal airline accidents. A whole class of turbulence, representing 40% of turbulence accidents, and designated as Clear Air Turbulence, cannot be detected by any existing airborne equipment, including state-of-the-art weather radar; this explains that the number of turbulence accidents has been growing by a factor of 5 since 1980, 3 times faster than the increase of the air traffic.

Operational concepts for the protection against turbulence hazards include:

  • Short-range (50 m to 300 m) measurement of air speed ahead of the aircraft, and action on the aircraft flight controls to mitigate the effect of turbulence
  • Medium-range (10 km to 30 km) detection of turbulence, and securing of passengers and crewmembers by seat belts fasten

Both concepts are based on the UV LIDAR technology. The short-range concept was validated in the frame of the FP5 AWIATOR project. The objective of DELICAT is to validate the concept of LIDAR based medium range turbulence detection.

Both short and medium range concepts are based on the UV LIDAR technology, and there would be a great interest in integrating both functions into a single LIDAR system, for operational reasons (medium range detection increasing the overall reliability and integrity of the system) and economical reasons. There is no example of such equipment currently available.

The validation of medium range turbulence detection is based on the comparison of the information on a turbulent atmospheric area, provided on one side by the remote UV LIDAR and on the other side by the aircraft sensors (acceleration, air speed, temperature). This validation includes the following steps:

  • A UV LIDAR mock up is designed and manufactured, tested in laboratory on the ground, and then installed onboard a research aircraft, which is intended to fly in turbulent and non-turbulent conditions
  • During the flight tests, the atmosphere is analysed by the UV LIDAR and also by the aircraft onboard sensors
  • The data obtained from the LIDAR and from the aircraft sensors are compared off line once the aircraft on the ground. The correspondence between LIDAR backscattered energy fluctuations and turbulence experienced by the aircraft, for a given atmosphere area, is assessed and evaluated

The consortium assembled for the DELICAT project includes all the expertise necessary to reach the objective (project management, LIDAR design and manufacturing, Clear Air Turbulence forecasting, on board sensors, flight tests, data processing), and will take advantage of previous projects such as AWIATOR and FLYSAFE. The project resources are adequately balanced between the different activities and are globally adapted to the project objectives and innovation content. DELICAT takes advantage of existing hardware (laser sub assemblies, test aircraft fairing) to achieve the goal at lower possible cost.

The DELICAT project will directly contribute to the objectives of the AAT.2008.3.3.2. Topic by validating an advanced technology for aircraft protection against Clear Air Turbulence hazards. This will increase both customer satisfaction and aviation safety; based on traffic and accidents statistics, one can estimate that such a UV LIDAR turbulence protection equipment would have avoided 8 to 10 turbulence accidents in 2005 and will reduce by 15 to 20, or 40%, the number of turbulence accidents per year, once developed.