IRFP-01
Metro Review
d. Intense horizontal outflows at low altitudes result in extreme
head wind to tail wind differentials that have been recorded in
excess of 200 kts
e. Experience has shown that microbursts are not isolated, but
usually occur in groups
2. Effects: a microburst approach scenario
Note: Microbursts can be encountered in the head wind, down-
draft, or tail wind phase. The scenario below exemplifies an
approach in which the aircraft enters a fully developed microburst
at the rolling outflow. Pilot reactions depicted in the sequence are
based on cockpit indications—with pilot unaware of the microburst.
a. Initial entry of aircraft into microburst (head wind and updraft)
(1) Conditions: airspeed and AOA increase, producing more
lift and causing the aircraft to pitch nose high and to go
high
(2) Indications: AOA indexer displays “slow” and glideslope
shows high
(3) Normal pilot response: reduces power and AOA
(4) Effects: stops the climb and reestablishes descent rate
and on-speed AOA
b. Outflow area prior to microburst core (head wind shifting to
downdraft)
(1) Conditions
(a) Airspeed and AOA decrease due to shift in air mass
movement, reducing lift
(b) Descent rate increases
(2) Indications: AOA indexer “fast,” VSI shows increased rate
of descent, and airspeed begins to fall
(3) Normal pilot response
(a) Raises nose attitude to correct for “fast”
(b) Delays power application due to continued high
indication
(4) Effects: energy loss is undetected
(8-97) Original
Page 1-19
Previous Page
