In some cases, an Alternate G/S Cancel is available. This allows
the Mode 5 alerting to be canceled at any time and any altitude.
In this configuration, which is defined only for certain aircraft
types or by program pin, pressing the G/S Cancel switch in the
cockpit has the effect of inhibiting Mode 5 alerting. It can be
manually reset by again pressing the G/S Cancel switch, or it is
automatically reset following landing, if flap or gear state
changes (i.e., down to up), or when the aircraft climbs above a
predetermined altitude (defined for the aircraft type). Because
of the nature of this type of G/S Cancel, a cockpit indication of
its activation is required.
Some aircraft may be configured with a G/S inhibit switch.
This switch is separate from the one discussed above but also
results in inhibiting Mode 5 alerting. This switch is intended
for selection during back course approaches to eliminate
unwanted alerts that may result. If a discrete back course
signal is available from another system, this input to the
EGPWC may be connected to that system for automatic
Mode 5 inhibiting.
NOTE: Implementation of the Glideslope Cancel and/or
Inhibit inputs to the EGPWS varies. Verify a particular
application to determine the implementation used.
Pressing the Terrain Inhibit switch inhibits TAD and TCF
alerting and display, including Obstacles and Peaks when
enabled. This is used when position accuracy is inadequate or
when operating at airports not in the terrain database.
Selection of Terrain Inhibit does not cause the Terrain
Inoperative annunciation unless the aircraft is wired for this to
occur. Terrain Inhibit requires manual deactivation.
The EGPWS Flap or Gear Over-ride, TAD/TCF Inhibit, or other
switches (as installed) may be used as required for an
emergency situation (e.g., landing gear up).
For additional information refer to an applicable AFM or
EGPWS AFMS or contact Honeywell.
060-4241-000 • Rev. D - March 2000
MK V & MK VII EGPWS Pilot Guide