Mark V and Mark VII EGPWS Pilot’s Guide
060-4241-000
System Description
Rev H, August 2011
19
MODE 5
Continued
•
The upper altitude limit for the alert is modulated with
vertical speed. For descent rates above 500 FPM, the upper
limit is set to the normal 1000 feet AGL. For descent rates
lower than 500 FPM, the upper limit is desensitized
(reduced) to a minimum of 500 feet AGL.
Additionally, both alert levels are desensitized below 150 feet
AGL, to allow for normal beam variations nearer the ground,
and reduce the possibility of nuisance alerts.
If the Aural Declutter feature is disabled, messages are
repeated continuously until the Mode 5 envelope is exited.
Mode 5 alerts can be canceled by pressing the Glideslope
Cancel switch (if installed). The EGPWS will interpret this
switch one of two ways depending on the installation
configuration.
•
A
standard
glideslope cancel switch allows for manually
canceling Mode 5 alerting any time below 2000 feet AGL.
This is automatically reset when the aircraft descends
below 50 feet or climbs above 2000 feet AGL (1000 feet
AGL for current Boeing production aircraft).
•
An
alternate
glideslope cancel switch allows for manually
canceling Mode 5 alerting at any time and any altitude. The
cancel is reset by again pressing the cancel switch, or
automatically if gear or flaps are raised, or the aircraft is on
the ground. Due to the nature of the alternate cancel switch,
this method requires that there be a cockpit annunciation
that glideslope cancel is in effect (this configuration is
currently not allowed on aircraft operating under FAA part
121 rules).
EGPWS Mode 5 alerts are inhibited during backcourse
approaches to prevent nuisance alerts due to false fly up lobes
from the Glideslope. The EGPWC determines a backcourse
approach if either: 1) the aircraft’s magnetic track is greater
than 90 degrees from the runways approach course, or 2) a
glideslope inhibit discrete is set.
MODE 6
Advisory
Callouts
Mode 6 provides EGPWS advisory callouts based on the
menu-selected option established at installation (set by
program pin configuration). These callouts consist of
predefined Radio Altitude based voice callouts or tones and an
excessive bank angle advisory. There is no visual alerting
provided with these callouts.
Summary of Contents for EGPWS MK V
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