Microburst and Low level Windshear Perceptions
Making the Skies Safe from Windshear it is very
important to understand well the concept as Pilots.
In our profession as Pilots all must always
need to understand altogether the conceptions and perceptions related to bad
weather when flying.
It seems the terms Microburst and Windshear
have been in our Pilots vocabulary for many years, so in fact the current
information we as pilots have today evolved from research conducted to avoid
and identified the weather activity associated with each type of microburst and
low level windshear.
The most important it is to identify the cues
present during windshear activity.
All pilots must understand and be able to identify
at any time when flying, to identify the weather activity associated with bad
weather during an approach or any other phase of the flight.
Meteorologist considered a downdraft as the
most hazardous activity associated with a thunderstorm.
To be more explicit the conventional theory was
that a downdraft was strongest inside or directly beneath the cloud, it was
thought to significantly deteriorate long before reaching the ground, and as a
result there was little danger in an outflow of wind disturbance.
To have more idea about the term Microburst the
study and identification began in 1974, when Professor Theodore Fujita, of the
University of Chicago, began his world renown research on weather phenomenon.
Fujita aggressively pursued the causes of aircraft accidents around
thunderstorms activity.
I am a person who likes to read and do a lot of
research regarding why accidents happen and also to share with the aviation
community through my Safety Blog to all pilots to stay away from accidents.
Remembered too that in a book I read about accidents in the past, involved some
aircrafts like the Southern Airways DC 9 crashed as a result of those storms in
the South East area in the United Sates.
A year later after 1974 an Eastern Airlines a B
727 crashed at JFK, while attempting to land in a thunderstorm. Maybe some Seniority pilots who have the
chance to read this post remember what I’m talking about it in these accidents
concerning thunderstorms on that year.
In 1978 Professor Fujita had collected enough
data to change the minds of the skeptics.
The first field program on downburst was
conducted by the University of Chicago, and operated for 42 days, by using
three strategically placed Doppler Radars and other measuring equipment. Fujita
and his team discovered the phenomena of Macroburst and Microburst in the early
1980.
According to Professor Fujita a downburst is
subdivided into Macroburst and Microburst.
All of these concepts are good to review to be constantly
a Safety Pilot, anyway the most important it is to understand the types of
microburst to have a safely flight when you will be encountered or hear during
your flight this term to avoid an incident or accident related with
thunderstorms and bad weather.
Macroburst: A large downburst with is outburst
winds extending in excess of 4 kms (2.5 miles) in horizontal dimension. An
intense Macroburst often causes widespread, tornado like damage, damaging
winds, lasting 5 to 30 minutes, could be as high as 60 meters / second, or 134
mph.
Microburst: A small downburst with its outburst,
damaging winds extending only 4 Kms or less, in spite of its small horizontal
scale, an intense Microburst could induce damaging winds as high as 75 meters/
second or 168 mph.
I want to share with all Private and Commercial
Pilots that not all microburst are alike, some are accompanied by heavy rain
while others form beneath the term small virga .
There are: Wet Microburst, Dry Microburst ,
Traveling Microburst, Radial Microburst , Twisting Microburst , Surface
Microburst , Outflow Microburst , and Rotor Microburst .
Let’s review some about Low –level Windshear :
Windshear is a change in wind speed, direction, or both over a short distance .
There are several weather phenomena that produce such conditions. These include
thunderstorms, fronts, radiation inversions, directing winds, and mountain
waves.
Windshear studies started in 1986 with
analysis, moved to simulation and now are in the flight-test stage. Pilots
always keep in mind Windshear poses the greatest danger to aircraft during
takeoff and landing, when the plane is close to the ground and has little time
or chance to maneuver.
NASA said there are three airborne predictive
windshear sensor systems; Pilots need 10
to 40 seconds of warning to avoid windshear. Fewer than 10 seconds is not enough time to react, while more than 40
seconds is too long, atmospheric conditions can change in that time.
Three systems are being flight-tested to give
advance warning of windshear: Microwave radar, Doppler LIDAR, Infrared.
NASA and the FAA: Working together for a
solution to prevent future accidents.
Remember always the more you know the more you
grow as an Aviator, a Safety Pilot is who anticipating abnormal flight
characteristics , this is the key to successfully flying through a windshear
encounter.
The best Pilot is the one who has sense enough
to pick good things during flying and always is a conservative airman all the
time, to stay away from accidents.
THINK SAFETY! Watch your THOUGHTS
hi
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