Helicopters Magazine

AWI Model 8339 Laser Ceilometer Certified by FAA

November 20, 2007  By Corrie

awi8339Nov. 20, 2007, Sacramento, CA- All Weather, Inc. of Sacramento, California has announced that its new laser-based ceilometer—a device for measuring the height and thickness of cloud cover—has been certified by the Federal Aviation Administration.

awi8339Nov. 20, 2007, Sacramento, CA – All Weather, Inc. of Sacramento, California has announced that its
new laser-based ceilometer—a device for measuring the height and
thickness of cloud cover—has been certified by the Federal Aviation
Administration for use in airport weather stations. The Model 8339
ceilometer marks a major advance in the ability of airports to
communicate cloud conditions to pilots with consistent accuracy and

The Model 8339 is the first ceilometer to
simultaneously detect and measure up to four layers of clouds. It is
able to detect clouds up to an altitude of 25,000 feet, with its upper
limit capped at 12,500 feet in FAA applications. This combination of
range and cloud resolution provides more accurate data in all weather
conditions, even heavy precipitation and low clouds. The Model 8339
discerns extremely thin obscurations, with a resolution of 12.5 feet
over its full range. Both vertical visibility and ground-based
obscurations can be reported in addition to higher layers of clouds.

Model 8339 fills a vital niche in weather reporting," said Don Soenen,
President of AWI. "Our goal is to provide airports and meteorological
stations with the critical weather information they need, even when the
skies are obscured.”

Reliable and accurate Light Detection And
Ranging optical radar (LiDAR) is the Model 8339's core technology. A
low-power laser transmitter with a high-reliability gallium arsenide
diode transmits light pulses, which are scattered and partially
reflected by cloud cover in their path. A silicon avalanche photodiode
receiver captures the returning signal, and the ceilometer's
sophisticated signal processing is applied to extract accurate cloud
height and depth from the signal. The receiver is adjustable to allow
for gain and response control in varying environmental conditions.


digital signal processing algorithms ensure the Model 8339 provides
accurate reporting of cloud base locations in all weather conditions.
The selectable range of 30, 60, or 120 second measurement intervals
means a high degree of flexibility for a variety of aviation weather
applications. The sensor's comprehensive flexibility extends to its
output options as well, with RS485 and RS232 outputs providing for data
transmission over both long and short distances.

to Federal Aviation Administration AWOS (Automated Weather Observing
System) and National Weather Service ASOS (Automated Surface Observing
System) standards, the Model 8339’s rugged, weatherproof housing
protects the unit in extreme operating conditions, from –40˚C to
+60˚C.  A sophisticated array of built-in tests executes in the
background during operation to ensure consistent sensor operation.
During snow, rain, and ice conditions, a powerful heater/blower keeps
the lenses clear, and a "dirty window" detector notifies the operator
when dust, water, or contaminants have accumulated on the sensor's

No consumables are required in the operation of the Model
8339, such as blower filters and desiccants used in most other models,
keeping maintenance of the sensor to a minimum.

About All Weather Inc.
All Weather, Inc. (AWI) is a
leading developer of high-accuracy, high-dependability weather
information systems that help users minimize risks in an unpredictable
world. The company provides AWOS aviation weather systems and air
traffic control display systems, as well as a wide range of
high-accuracy meteorological sensors and systems, including laser
ceilometers, runway visual range systems, lightning detection sensors,
and a variety of other meteorological sensors. AWI’s ASOS, AWOS, and
AWSS systems meet the stringent standards of the International Civil
Aviation Organization (ICAO),
the World Meteorological Organization (WMO),
FAA, and Transport Canada.
AWI has installed more than 2000 high-end automated weather systems
around the globe, working with such leading authorities as the U.S.
National Weather Service, FAA, ICAO, WMO and commercial users around
the world. For more information, see www.allweatherinc.com.


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