Inhibit Mode; External Taws Inhibit Control; Taws Manual Test - Garmin GNC 420AW Pilot's Manual

Part Three: Section 2
TAWS Operation

Inhibit Mode

TAWS provides an "inhibit mode". This mode is
designed to deactivate PDA/FLTA aural and visual
alerts when they are deemed unnecessary by the
aircrew. Flying VFR into an area where unique terrain
exists could cause the system to annunciate a nuisance
alert. Pilots should use discretion when inhibiting
the TAWS system and always remember to enable the
system when appropriate. Only the PDA and FLTA
alerts are disabled in the inhibit mode. See section 3
for more information on TAWS alerts.
TERRAIN configured units will restore the "inhibit
state" at startup to the last pilot-selected setting. TAWS
configured units will always start up with TAWS alerts
uninhibited.
Inhibiting Terrain
To inhibit PDA and FLTA alerts:
Select the TAWS Page and press MENU.
1.
"Inhibit Terrain?" is selected by default.
2. Press ENT. The PDA/FLTA alerts are inhibited.
34
The
the terrain annunciator field whenever TAWS
is inhibited.
To enable PDA and FLTA alerts:
Select the TAWS Page and press MENU.
1.
"Enable Terrain?" is selected by default.
2. Press ENT. The PDA/FLTA alerts are functional
again.

External TAWS Inhibit Control

An optional installation is allowed for providing
an external TAWS Inhibit switch. Pressing the external
TAWS Inhibit switch toggles the TAWS inhibit on and off
in the same manner as using the Page Menu selection.

TAWS Manual Test

Garmin TAWS provides a manual test capability
which verifies the proper operation of the aural and
visual annunciations of the system prior to a flight.
To manually test the TAWS system:
Select the TAWS Page and press MENU.
1.
2. Select the "Test TAWS?" option.
3. Press ENT to confirm the selection.
An aural message is played giving the test results:
• "TAWS System Test, OK" if the system passes the
test
• "TAWS System Failure" if the system fails the test
NOTE: TAWS System Testing is disabled when ground
speed exceeds 30 knots so as not to impede TAWS alert-
ing.
190-00356-30 Rev H
annunciation is displayed in
"Test TAWS" selection