Most planes fly out of their way to avoid atmospheric
turbulence, but not a former airliner now outfitted as a NASA
flying laboratory.

A 757 research aircraft, based at NASA’s Langley Research
Center in Hampton, Va., went searching for thunderstorms for
eight weeks this spring. 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 the air.

“NASA is working on an enhanced turbulence detection radar
system, which is a software signal processing upgrade to
existing predictive Doppler wind shear systems already on
airplanes,” said Jim Watson, deputy turbulence prediction and
warning systems project manager.

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.

“Most people try to avoid the weather we’re trying to go to.
We want to see the storm. We want to go near the storm —
within a safe distance,” said Neil O’Connor, 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 aircraft
radar would not have seen it,” said O’Connor.

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 we’re looking at having some
significant improvements on 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 (FAA) 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 arrivals.

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
accideonalate 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: http://avsp.larc.nasa.gov

-end-

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. 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.