Honeywell MK VI - Manual (Page 316)

Honeywell
MK VI MK VIII EGPWS Installation Design Guide
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7.4.2 Audio On Discrete
The Audio On discrete goes true whenever any voice message is being enunciated. It will stay true until the voice is
completed. This output can be used to inhibit other audio systems (e.g., TCAS) during EGPWS audio or used to drive the
audio key line input provided on some aircraft audio systems.
7.4.3 Monitor Discretes (GPWS INOP & Terrain INOP or Terrain Not Available)
The EGPWC produces two discrete monitor outputs. These discretes reflect the GPWS INOP and Terrain INOP / Terrain
Not Available functions. These discretes activate with loss of EGPWC power. The status of these two discretes is also
contained on an ARINC 429 output word.
Note: Some display systems provide one message area for both warning and associated INOP annunciation. There are
conditions where GPW INOP and a GPWS warning can exist at the same time (e.g., Sinkrate warning can occur even if a
Ground Airspeed input fault exists.) For these installations a configuration item INOP & Warning Annunciation in Same
Window is provided which causes the INOP annunciation to extinguish whenever a valid warning annunciation is
required. Various formats of monitor outputs can be provided as defined in Category 13.
7.4.4 Terrain Display Switching Discretes (WxR/EGPWS Display Select)
The EGPWC produces two discrete outputs for controlling the terrain display(s). They can be used either to control
picture bus switching relay(s) or connected directly to the symbol generator(s).
7.4.5 Flap Override Discrete
The MK VI EGPWC Flap Override function can be selected by the pilot to desensitize the alert and warning modes. The
Flap Override discrete output is active (Gnd) whenever the Flap Override has been selected and is typically used to drive a
lamp.
7.4.6 Glideslope Cancel Discrete
The Glideslope Cancel discrete is active whenever Glideslope Cancel has been selected and is typically used to drive a
lamp in the Glideslope Cancel switch.
7.4.7 Terrain / Obstacle Awareness Alert Discretes
Terrain Awareness provides discrete alert outputs for Terrain / Obstacle Cautions and Warnings. These outputs can drive
cockpit lamps or act as discrete inputs to other aircraft systems.
7.4.7.1 Terrain / Obstacle Caution
Terrain and Obstacle Cautions can be configured to activate any of the discrete outputs. Depending on configuration, the
Caution discretes will typically activate either the GPWS Warn Lamp, the GPSW Alert Lamp, or will drive their own
output lamps.
7.4.7.2 Terrain / Obstacle Warning
Terrain and Obstacle Warnings can be configured to activate any of the discrete outputs. Depending on configuration, the
Warning discretes will typically activate either the GPWS Warn Lamp or will drive their own output lamps.
7.4.8 Terrain Pop Up
The Terrain and Obstacle Caution and Warning are combined (Or’d) on one discrete to make a Terrain Pop Up indication
for an integrated display system. The Pop Up discrete can be used by a display system to differentiate between a manual
selection or one due to a Terrain/Obstacle Caution or Warning event.
7.4.9 Windshear INOP Monitor Discretes
The MK VIII EGPWC also produces an additional discrete monitor output for Windshear. This discrete reflects the
WINDSHEAR INOP functions. The status of this discrete is also contained on an ARINC 429 output word.
7.4.10 Windshear Warning
The MK VIII EGPWC Windshear Warnings can be configured to activate any of the discrete outputs. Depending on
configuration, the Warning discrete will typically drive its own output lamp or provide a discrete output to other aircraft
systems.