Terrain/Obstacle Database Areas Of Coverage; Navigation Database; Taws Phase Of Flight - Garmin GNC 420W Pilot's Manual Addendum

To update your terrain/obstacle databases:
1. Acquire a new terrain data card from
Garmin.
2. Turn off the power to the 500W Series unit.
3. Remove the old terrain data card and insert the
new card into the right-most slot of the 500W
Series unit.
4. Turn on the 500W Series unit and verify that
the TAWS system passes self-test.

Terrain/Obstacle Database Areas of Coverage

The following describes the area of coverage avail-
able in each database. Regional definitions may change
without notice.
The terrain and airport terrain databases include
worldwide coverage that includes: Latitudes South 60°
to North 75°.
The obstacle database provides coverage for the
USA and Europe that includes:
United States: Limited to the United States, some
areas of Canada, Mexico, the Caribbean, and the
Pacific.
Europe: Limited to Austria, Belgium, Czech Repub-
lic, Denmark, Estonia, Finland, France, Germany,
Greece, Iceland, Ireland, Italy, Latvia, Lithuania, Neth-
erlands, Norway, Poland, Portugal, Slovakia, Spain,
Sweden, Switzerland, and the United Kingdom.
NOTE: Obstacles 200 feet and higher are included in
the Obstacle Database. It is very important to note that
not all obstacles are necessarily charted and therefore
may not be contained in the Obstacle Database.

Navigation Database

As explained in the "Premature Descent Alerting
(PDA)" section, Garmin TAWS Premature Descent
Alerting (PDA) algorithms utilize data contained in
the navigation database. It is therefore important to
also have the latest navigation database installed to
ensure correct TAWS alerting.

TAWS Phase of Flight

The TAWS Phase of Flight definitions are listed
below:
En Route Phase - Defined as when the aircraft
is more than 15 NM from the destination airport, or
when the conditions for Terminal, Approach, and
Departure Phases are not met.
Terminal Phase - Defined as when all three of the
following conditions are met:
• The aircraft is 15 NM or less from the destina-
tion runway.
• The distance to the destination runway thresh-
old is decreasing.
• The aircraft is at or below (lower than) a
straight line drawn between the two points
specified in the table below (relative to the
destination runway).
Distance to Runway
15 NM
5 NM
Approach Phase - Defined as when all three of
the following conditions are met:
• The distance to the destination runway thresh-
old is equal to or less than 5 NM.
• The height above the destination runway
threshold elevation is equal to or less than 1000
feet.
• The distance to the destination runway thresh-
old is decreasing.
Part Three: Section 3
TAWS Operation
Height above Runway
3500 feet
1900 feet
35