Metro-01
Review of Basic Meteorological Principles
3.
Indications of microburst activity
a.
Blowing dust, dust devils, and gust fronts (downbursts will
occasionally generate distinctive circular dust patterns)
b.
Thunderstorms in vicinity with visible areas of intense
downdrafts indicated by rain or virga
c.
Sudden and unexplained increase in airspeed as noted on
airspeed indicator accompanied by increased AOA--indicative
of rolling outflow
d.
Sudden increase in rate of descent accompanied by a lower
AOA--indicative of entry into microburst core
e.
Extreme variations in wind velocity and direction in short time
f.
Significant differences between winds at 1,500 to 2,000 ft AGL
surface winds
g.
LLWAS (Low-Level Windshear Alert System) alert
NOTE: The LLWAS is comprised of a series of wind sensors
located at various positions on the airport. The system senses
windshear occurrences through comparison of readings from
the various wind sensors. LLWASs are installed at several
major airports around the U.S. Unfortunately, some micro-
bursts are so small that they can fit between the sensors.
Doppler radar has proven effective in detecting microbursts
and is being installed at major airports.
h.
PIREP of windshear or airspeed gain or loss
NOTE: Although PIREPs are important to alert other pilots of
microbursts, microburst intensity can change rapidly, so even
recent PIREPs may not reflect the true strength of a
microburst--listen to the aircraft ahead or ask for PIREP
information from ATC. Report any airspeed fluctuations of 5
kts or more as soon as possible.
4.
a.
Takeoff: delay departure
b.
Landing: delay approach or use alternate runway/approach or
proceed to nearby alternate
5.
Response during landing
a.
Execute a missed approach immediately--response time is
critical
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