060-4241-000 • Rev. D - March 2000
MK V & MK VII EGPWS Pilot Guide
Mode 7 is designed to provide alerts if the aircraft encounters
windshear. Two alerting envelopes provide either a Windshear
Caution alert or a Windshear Warning alert each with distinctive
aural and visual indications to the flight crew.
EGPWS windshear is provided for certain (not all) aircraft types
and is a function of certain additionally required input signals
and enabled internal detection algorithms. These are
established during the initial installation and addressed in the
appropriate Airplane Flight Manual (AFM) or EGPWS Airplane
Flight Manual Supplement (AFMS).
Windshear Caution alerts are given if an increasing headwind
(or decreasing tailwind) and/or a severe updraft exceed a
defined threshold. These are characteristic of conditions
preceding an encounter with a microburst.
A Windshear Caution if enabled results in illumination of
amber Windshear Caution lights and the aural message
"CAUTION, WINDSHEAR". The lights remain on for as long as
the aircraft is exposed to conditions in excess of the caution alert
threshold. The Windshear Caution envelope is illustrated in the
The Windshear Caution alerting can be disabled by EGPWS
program pin selection so that only Windshear Warning alerts