Embraer EMB145 - Page 1671

CREW
AWARENESS
AIRPLANE
OPERATIONS
MANUAL
2-04-35
Page
4
Code
01
REVISION 39
AOM-145/1114
WINDSHEAR DETECTION
The windshear detection system is designed to identify the presence
of severe windshear phenomenon and to provide timely warnings and
adequate flight guidance for approach, missed approach, takeoff and
climb out.
The windshear computer exchanges data with AHRS, ADC, SPS,
Radio Altimeter and IC-600s. The system continuously searches for
any windshear clue, and then signals the PFD and aural warning unit
to provide the appropriate indications.
Windshear Caution alerts are given if the windshear consists of an
increasing headwind (or decreasing tailwind) and/or severe updraft,
which may precede an encounter with a microburst. Windshear
cautions activate the Windshear Caution (WDSHEAR) amber
indications on the upper left corner of both PFDs. On airplanes
equipped with EGPWS, an aural message “CAUTION WINDSHEAR”
is also triggered. Windshear Caution indications remain on for as long
as the airplane remains exposed to an increasing headwind and/or
updraft condition in excess of the alert threshold.
Windshear Warnings are given if the windshear consists of a
decreasing headwind (or increasing tailwind) and/or severe
downdraft. Windshear warnings activate the Windshear Warning
(WDSHEAR) red indication on both PFDs and trigger an aural
message “WINDSHEAR, WINDSHEAR, WINDSHEAR”. This message
will not be repeated unless another, separate, severe windshear event
is encountered. Windshear Warning indications remain on for as long
as the airplane remains exposed to a decreasing headwind and/or
downdraft in excess of the alert threshold. The threshold is adjusted in
function of available climb performance, flight path angle, airspeeds
significantly different from normal approach speeds and unusual
fluctuations in Static Air Temperature (typically associated with the
leading edges of microbursts).