Honeywell KLN 90B GPS Abbreviated Operation Manual page 53

NOTE: There may be some difference (less than 100 feet) between the
indicated altitude (IND) and the aircraft's actual altitude if the altitude input
to the KLN 90B is from an altitude encoder because these encoders only
provide altitude in 100 foot increments.
3. Turn the left outer knob one step clockwise to position the cursor over
the ALERT: field. If OFF is displayed, turn the left inner knob to select
ON. When alerting is enabled, an arrow to the right of ON points to the
selected altitude on the right side of the screen.
4. Select a warn altitude by using the left outer knob to position the cursor
over the WARN: field. Use the left inner knob to select the desired warn
altitude. It is selectable in one hundred foot increments up to 900 feet.
Normally, you will use the same warn altitude all the time so you only
have to enter this the first time you use altitude alerting. The recom-
mended warn altitude is 300 feet.
5. Enter the selected altitude one digit at a time in the SEL field of the NAV
4 page by using the right outer knob to position the cursor over the
desired digit and the right inner knob to change the digits until the entire
selected altitude is displayed .
Only the selected altitude field (SEL) and the indicated altitude (IND) of
the NAV 4 page are used for altitude alerting. The rest of the NAV 4 page
is used for vertical navigation which is described in section 5.2 on the KLN
90B Pilot's Guide.
6. Press A to return to the pages previously being displayed.
7. The aural alarm activates as follows:
• 1000 feet prior to reaching the selected altitude - alert by three
short tones
• Upon reaching the selected altitude - alert by two short tones
• Deviating above or below the selected altitude by more than the
warn altitude - alert by four short tones
NOTE: Due to the resolution of the altitude input, it may be necessary to
descend slightly below or climb slightly above the selected altitude before
the two tones are activated indicating that the selected altitude has been
reached. This selected altitude alert must be activated to arm the system
for providing the altitude deviation alert.
The KLN 90B can provide the aural alarm tones in either of two ways: it
may be connected to an audio input of an audio amplifier contained in an
audio panel so that the aural alarm is heard through the aircraft's speaker
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