RELEASE NO. 02-040
RESEARCHERS HUNT FOR TURBULENCE
NASA works to help pilots weather the skies
Most planes fly out of their way to avoid atmospheric
turbulence, but not a former airliner now outfitted as a NASA
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A NASA 757 research aircraft, based at NASAs Langley
Research Center in Hampton, Va., went searching for thunderstorms
over an eight-week period this spring. On board researchers with
the NASA Aviation Safety Program (AvSP) were testing a new way to
predict turbulence associated with those convective storms.
The 757 Airborne Research Integrated Experiments System (ARIES)
is equipped with an experimental radar system designed to detect
atmospheric turbulence by measuring the motions of the moisture in
"NASA is working on an enhanced turbulence detection radar
system, which is a software signal processing upgrade to existing
predictive Doppler wind shear systems that are already on
airplanes," said Jim Watson, deputy Turbulence Prediction and
Warning Systems project manager. "There are very sophisticated
algorithms that are designed to predict turbulence in front of the
airplane and then relate those to safety measures that are
dependent upon the aircraft itself. The complexity is great. It is
a software/hardware intensive upgrade."
To see how well the enhanced radar performed, the 757 and its
crew of two dozen researchers and technicians had to find the kind
of bumpy weather most airline passengers find uncomfortable.
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"Most people do try to avoid the weather were trying to go
to. We want to see the storm. We want to go near the storm --
within a safe distance," said Neil OConnor, Langley aerospace
researcher. "We want to experience the turbulence and compare what
our radars predicted versus what we experienced."
ARIES flew 13 research missions in search of convective
turbulence. The jet would leave NASA Langley in Virginia and fly to
areas where thunderstorms were predicted east of the Mississippi.
NASA research pilots circled the thunderstorms repeatedly to
subject the plane to rough air.
Inside the 757, researchers at test stations recorded conditions
and also alerted the pilots when and where they were likely to
encounter turbulence and how much. "The turbulence radar saw it
coming where the standard planes radar would not have seen
it," said OConnor.
Airliners are not currently equipped with turbulence detection
systems. "Pilots predict turbulence ahead by experience and
intuition, getting information from other airplanes that have
encountered turbulence close by and extrapolating the existing
weather radar system," Watson said. He added, "I think that
were looking at having some significant improvements coming
on the aircraft within the next one to two years."
Atmospheric turbulence is the leading cause of in-flight
injuries to airline passengers and flight crews. Federal Aviation
Administration statistics show that 98 percent of those injuries
happened because people were not wearing seat belts. An alert of
impending rough air would give pilots time to warn passengers and
flight attendants to buckle up and take steps to reduce turbulence
effects. Turbulence is not only hazardous, it also costs the
airlines money and time, in the form of re-routing and late
To tackle turbulence, the NASA Aviation Safety Program (AvSP)
- Developing better forecasting techniques
- Drafting a turbulence characteristics scale
- Researching and testing detection technologies
- Studying methods to minimize turbulence effects
AvSP is a partnership with the FAA, aircraft manufacturers,
airlines and the Department of Defense. This partnership supports a
national goal to reduce the fatal aircraft accident rate by 80
percent in 10 years.
Researchers at four NASA field installations are working to
develop advanced, affordable technologies to make flying safer:
Langley; Ames Research Center at Moffett Field, Calif.; Dryden
Flight Research Center in Edwards, Calif.; and Glenn Research
Center in Cleveland, Ohio.
For more information on the NASA Aviation Safety Program please
check the Internet at:
Video of the flight tests is scheduled to be shown as part of
the daily NASA Video File on June 18 and 19 at noon, 3 p.m., 6 p.m.
and 9 p.m. Eastern. Changes in the Space Shuttle schedule may
affect Video File airings. NASA Television is broadcast on GE-2,
transponder 9C, C-Band, located at 85 degrees West longitude. The
frequency is 3880.0 MHz. Polarization is vertical and audio is
monaural at 6.8 MHz. Video and still photographs are also available
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