System Constraints - Honeywell MK VI Pilot's Manual

System
Constraints
060-4314-000 • Rev. C - May 2004
MK VI & MK VIII EGPWS Pilot Guide
System constraints for the EGPWS are:
• If terrain data is unavailable for a particular area (within the
region for a regional database), then Terrain and Obstacle
alerting is not available for that area and the affected display
area is colored MAGENTA. If outside the regional database,
the display is blank or turned off with a corresponding Ter-
rain inoperative or unavailable indication.
• The display of terrain and obstacle information is intended
to serve as a situational awareness tool. It does not provide
the accuracy and/or fidelity to be the sole source for deciding
terrain or obstacle avoidance. Navigation must not be predi-
cated upon the use of the EGPWS terrain/obstacle display.
• If there is no source of aircraft position data meeting the
accuracy requirements for the TAD and TCF functions, then
these enhanced functions are automatically inhibited with a
resultant Terrain inoperative or unavailable indication.
• TAD/TCF functions should be manually inhibited when within
15 NM and on approach to an airport or runway that is not in
the airport database to avoid unwanted alerts.
• TAD/TCF functions should be manually inhibited for ditching
or other off-airport landings.
• When the TAD/TCF functions are inhibited and the EGPWS is
otherwise functional, the EGPWS reverts to providing basic
GPWS functions (Modes 1 to 6). In this state, the EGPWS
may give little or no advance warning time for flight into
precipitous terrain where there are few or no preceding ob-
structions. This particularly applies if:
• The aircraft is in the landing configuration,
• The aircraft is in a stabilized descent at a normal ap-
proach descent rate,
• There is no ILS Glideslope signal being received by the
EGPWS (not tuned, not available, or inoperative)
• Terrain clearance or descent rates that are not compatible
with required minimum regulatory standards for Ground
Proximity Warning equipment may cause unwanted alerts.
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