Aircraft

Laser-based turbulence detector could mean safer flights

Laser-based turbulence detecto...
View from the aircraft testing the Ultraviolet "Light Detection and Ranging" (LIDAR) instrument (Photo: DLR (CC-BY 3.0))
View from the aircraft testing the Ultraviolet "Light Detection and Ranging" (LIDAR) instrument (Photo: DLR (CC-BY 3.0))
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Kelvin-Helmholtz clouds caused by turbulence in the air (Photo: Astronautilus)
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Kelvin-Helmholtz clouds caused by turbulence in the air (Photo: Astronautilus)
View from the aircraft testing the Ultraviolet "Light Detection and Ranging" (LIDAR) instrument (Photo: DLR (CC-BY 3.0))
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View from the aircraft testing the Ultraviolet "Light Detection and Ranging" (LIDAR) instrument (Photo: DLR (CC-BY 3.0))
The Ultraviolet 'Light Detection and Ranging' (LIDAR) instrument currently being tested to detect CAT (Photo: DLR (CC-BY 3.0))
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The Ultraviolet 'Light Detection and Ranging' (LIDAR) instrument currently being tested to detect CAT (Photo: DLR (CC-BY 3.0))
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For most air travelers, turbulence provides nothing more serious than the odd moment of extreme panic, but it costs airlines hundreds of millions of dollars each year in injury compensation and aircraft damage. There are various different types of turbulence, but the most dangerous, because it is invisible and extremely difficult to detect, is clear-air turbulence (CAT). A new CAT detection technology that could help pilots choose a smoother route is now being tested as part of a European joint project called DELICAT (Demonstration of LIDAR based CAT detection).

As its name suggests, CAT can occur when no clouds are visible, providing no visual cues of its presence. Occurring most often at altitudes of around 7,000 to 12,000 m (23,000 to 39,000 ft), CAT is caused when bodies of air moving at different speeds collide with each other. Researchers at the German Aerospace Center (DLR) say that recent atmospheric studies indicate that CAT will become an even bigger problem in the future as climate change is expected to increase the frequency of CAT.

To minimize the dangers of CAT, DLR and its DELICAT project partners are testing a laser-based measurement device on flights throughout Europe. The LIDAR (Light Detection and Ranging) instrument, which was developed by researchers at the DLR Institute of Atmospheric Physics, emits short-wave ultraviolet laser radiation in the direction of the flight. By measuring the reflected signal from oxygen and nitrogen molecules, the device can detect fluctuations in air density and provide a warning of CAT in advance.

The system has been installed on a modified Cessna Citation aircraft that will be used in a flight campaign throughout Europe until the end of August. At the end of the test flights, the measurement data will be analyzed. The data will not only be used to demonstrate the system’s efficacy, but will also provide the researchers with information on the conditions in which CAT is likely to form.

The research team hopes their work will lead to the development of a detection system that could be integrated into aircraft so that pilots would have advance warning of CAT, giving them the potential to fly around the turbulence or, failing that, time to ask passengers to buckle up.

Source: DLR

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4 comments
Robert Kelly
Will this tech some day help paragliders find thermals :)
Mr E
Once again I get to reminisce about the work we did at Laser Systems in Ann Arbor back in the 60's. We developed a CAT detection system utilizing a ruby laser and I believe we tested it in a Ford TriMotor. We were able to detect CAT out to about 1 mile but at 450 mph or more that doesn't leave time for avoidance. We had a pod mounted under each wing. One contained the laser and the other contained the detection system. This report doesn't indicate what kind of detection range they get with the UV LIDAR but hopefully it is enough to provide adequate response time.
Stephen N Russell
for all Exec jets, airlines, air cargo, Gen Av planes alone that fly above 30K feet must have.
Future3000
In late 80ies a genius german paragliding and hangglider enthusiast built a 3 D windshear warning system, which detected particle-movement in all directions up to 3.5 km ahead using LIDAR combined LDA. Built it for fun for paragliding, then sold it to Raytheon... then never heard someting of this technology.