Clear Air Turbulence Invisible
JAXA and Boeing testing the system
Others also testing
Japan Aerospace Exploration Agency (JAXA), the government’s primary agency for aerospace development and utilization, has developed an onboard clear-air turbulence detection system. The 185 pound instrument can detect Clear Air Turbulence (CAT) about 10 miles in front of an aircraft; that is about 70 seconds at cruising speed before hitting the invisible, turbulent movement of air masses in the sky. The goal of the JAXA SafeAvio project is to “halve aircraft accidents caused by clear-air turbulence.”
The Boeing Company is testing the JAXA avionics to determine if the SafeAvio can effectively detect CAT in time to adjust altitude to avoid it. The test platform is a Boeing ecoDemonstrator, a 777 freighter and the site is the Montana Aviation Research Company (a Boeing wholly owned company) in remote St. Marie, Montana.
“So, this would be integrated into a forward display … warning the pilots they’re coming up on turbulence,” said Boeing Flight Test Director Ian Mahler. “And there will actually be a little pop up over here that has a countdown that says severe turbulence, moderate turbulence or wind shear, in 59, 58. It will countdown in seconds. And give you a warning of exactly when it will hit.”
“On the left side of the plane is something called a fairing. It’s also known as a blister because it looks like a bulge coming from the smooth, round exterior of the plane. On the outside of that fairing is a window which protects a liquid-cooled infrared laser called LIDAR.”
“LIDAR is the same type of technology fired down out of the bottom of special airplanes thousands of times a second to create detailed photographic-like images of the earth. It’s used to find earthquake faults on land and can be used to find what are essentially faults in the air: inconsistencies in the way air moves or turbulence.”
The beam goes out the side, reflects off a mirror and is focused miles ahead of the airplane. It’s detecting tiny particles in the air called aerosols. But when those particles seem to slow down, speed up, or move up and down, that’s the warning.
Then the question becomes, where do you find clear air turbulence to test it?
“We wanted to find something where the turbulence was very predictable,” said Mike Carriker, Boeing’s top pilot for product development. “So over Kansas, over Garden City, Kansas, we found an altitude about 24,000 to 27,000 feet where the wind was just terrible. Just shaking everywhere. But it was smooth below and smooth above, so we could get down below it and climb up and see that it was ahead of us, and then see that it was going to quit as we went out the other side.”
“And during our testing we validated, and it was absolutely incredible, that we saw it go five, four, three two one. And then the people started feeling the bouncing. So, the technology works,” said Mahler.
“And the airplane’s doing six miles a minute, so you’d have to find it 30 or 40 miles out in front of you. That’s the technological end goal because we’d like to have enough time to put the carts away,” said Carriker, explaining that while it’s important for passengers to buckle up, carts could fly up and hit someone.
Now, the job is to make the system smaller, while making it look out miles farther where it’s hoped it will become a routine safety tool in the cockpit.
.The ecoDemonstrator program will provide JAXA with a great opportunity to develop he data needed to earn regulatory approval and airline purchases. Reliability/predictability is a critical element of the testing.
The JAXA project is not unique. NASA has been involved in developing a system: The Airborne Coherent LIDAR for Advanced In-flight Measurement (ACLAIM) project at NASA’s Dryden Flight Research Center and the European joint project called DELICAT (Demonstration of LIDAR based CAT detection).
Hopefully one of these projects will become a useful tool to reduce. If not eliminate these injuries.
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