Honeywell KLN 900s, Pilot'S Manual

Page: 85 / 224

3-58 Rev 2
3.16 HEIGHT ABOVE AIRPORT ALERT
The height above airport alert feature can provide you a
means of knowing when you are at traffic pattern altitude
or when you are at a fixed height above the airport where
you might perform any repetitive duty.
The height above airport feature works as follows: You
enable/disable this feature and select an offset height on
the SET 5 page (figure 3-182). When the height above
airport alert is enabled, the KLN 900 creates a 5 nm
radius cylinder of airspace centered on an airport. This
airport is any airport that is a Direct To waypoint or is the
“TO” waypoint in the active flight plan. The height of the
cylinder above the airport is the offset height you select
on the SET 5 page. The KLN 900 adds this offset height
to the elevation stored in the database for the airport.
The KLN 900 compares the aircraft’s position relative to
the cylinder and notifies you with an aural alert when the
aircraft first penetrates the cylinder (figure 3-183). The
alert consists of a short tone, followed by a long tone, fol-
lowed by a short tone.
HT ABOVE |
APT ALERT |
ON
|
|
APT ELEV |
[ 800ft |
SET 5
Figure 3-182
5
NM
Airport elevation
plus selected offset height
Figure 3-183
HT ABOVE |
APT ALERT |
ON
|
|
APT ELEV |
[
8 00ft |
CRSR
Figure 3-184
To enable or disable the height above airport alert, press
the left
C
. Use the left outer knob to position the cursor
over the enable/disable field. Turn the left inner knob to
select ON or OFF as desired. To select the offset height,
use the left outer knob to position the cursor over the off-
set field (figure 3-184). Turn the left inner knob to select
an offset between 800 feet and 2000 feet or between 240
meters and 610 meters. Press the left
C
to turn the
cursor off.
WARNING: The height above airport alert feature
does not serve the same function as a radar altime-
ter. It does not provide any warning about the air-
craft’s actual height above the airport’s surrounding
terrain.