february2023 - 33

Vaisala's FD70 is able to measure the drop-size
distribution and velocity of falling hydrometeors and
offer present weather detection of conditions that
were previously hard to identify.
forward scatter, with transmissometer
technology like Vaisala's LT31 transmissometer.
Forward scatter technology,
such as Vaisala's FD70, is, in addition to
the meteorological visibility (MOR), able
to measure the drop-size distribution and
velocity of falling hydrometeors and offer
present weather detection of conditions
that were previously hard to identify.
These advances enable automated
passenger airplanes can operate in icy
conditions, timely awareness is critical
for maintaining safe and efficient operations
for all types of aircraft.
Taking on Impaired Visibility
Across the globe, low visibility cancels,
delays or disrupts flights every day. From
rain, fog, snow, sleet and other particulate
matter, obscurants can negatively
affect visibility, which is especially crucial
when the aircraft is maneuvering on
or close to the ground.
Good visibility optimizes airport efficiency
by maximizing inbound/outbound
aircraft capacity, while impaired visibility
forces airport operations to slow down to
ensure safe departures and arrivals. Most
automated weather observing systems
struggle to identify these conditions,
and human observation is typically necessary
to validate the presence of icing.
Observers often compile their reports by
integrating sensor measurements with
visual observation of known landmarks,
but human estimation is subjective and
prone to error. Without reliable, accurate
visibility information, airports cannot
operate safely - nor at full capacity.
Categorized airports must have instrumented
meteorological optical range
(MOR) measurements and a system calculating
runway visual range (RVR), the
essential factor for enabling air traffic
control and pilots to make the correct
operational decisions. Visibility, or MOR,
can be measured with two approved
technologies: transmissometer and
weather observation platforms to accurately
identify real-time conditions in an
autonomous operating mode, delivering
detailed particle-by-particle analysis that
allows for highly reliable frozen-liquid
differentiation. The capability to differentiate
between frozen and liquid particles
and other precipitation identification is
essential for visibility and present weather,
including RVR.
Wind Shear: Addressing Shifts
in Wind Patterns
From wind shear and microbursts to gust
fronts and wind shifts, wind remains one
of the most dangerous - and difficult to
assess - weather hazards. While it may
not be the first weather event that comes
to mind when addressing winter storms,
the sudden change in the direction or
velocity of wind, also known as wind
shear, is an essential consideration. Most
commonly resulting in delays and cancellations,
wind shear can also quickly
create dangerous situations during takeoff
and landing when aircraft might not
be able to withstand severe wind-caused
disruptions to their flight paths.
While there is no mandate to measure
or detect wind shear, failure to do
so effectively can put lives at risk and
lead to crippling financial damages.
Consequently, the impact of wind shear
should be accounted for since it occurs
at a height and under flying conditions in
which aircraft are most vulnerable.
The best aviation weather management
systems for wind shear incorporate
a combination of up to three measurement
technologies: a low-level wind
shear alert system (LLWAS), weather
radar and scanning wind lidar. LLWAS
measures average wind speed and direction
using a network of remote ultrasonic
sensors fixed around runways and along
approach and departure corridors. In
addition, weather radar, used during
precipitation, can measure the wind field
from the entire aerodrome and beyond.
Scanning wind lidar, used in clear sky
conditions, provides wind shear detection,
3D wind information and wind
inversion detection that can measure
the entire field, from the runway and its
approach and take-off areas.
With real-time detection of wind shear,
decision-makers can predict wind changes
to prevent accidents and make runway
changes to improve airport efficiency.
Embracing Innovation in
Aviation
From maintaining scheduled operations
to keeping employees and travelers safe,
decision-makers with precise and timely
weather information can adapt, rapidly
react to changing conditions and reduce
disruptive delays. Technological advances
have opened the door for airport
decision-makers to measure and detect
severe weather and take the proactive
steps necessary to minimize delays and
cancellations while keeping operations
running as safely and smoothly as possible.
With the right aviation weather
solutions in place, airports can not only
be prepared for winter weather but have
the information on hand to address
any severe weather event throughout
the year.
ABOUT THE AUTHOR
KARI LUUKKONEN
Kari Luukkonen has a
long experience in various
roles at Vaisala. Over the
last five years, he has
been managing Vaisala's
offering for aviation
systems and services. His work includes
driving the development of the overall
weather offering to meet the current and
future needs of the aviation market.
February 2023 || AviationPros.com || 33
http://www.AviationPros.com
february2023

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