1. Press the altitude button. The
altitude page will be displayed on
the left with the cursor over the first
altimeter setting. The NAV 4 page
will be displayed on the right with
the cursor over the first digit of the
selected altitude field.
2. Use the left knobs to update the
altimeter setting, if required. There
are three cursor positions. Use the
left outer knob to move the cursor
and the left inner knob to change
altimeter setting, the indicated
altitude on the right should be the
There may be some difference (less than
100 feet) between the indicated altitude 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 then right side of the screen.
4. Select an amount of warning by
using the left outer knob to position
the cursor over the WARN field
and using the left inner knob to
select the amount of warning. It is
selectable in 100-foot increments
from 200 feet to 900 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.
6. Press altitude to return to the
pages previously displayed.
The altitudealerting feature will only be
accurate if the barometric altimeter setting
is kept updated.
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.
7. The altitude alert annunciator will
flash three times at 1,000 feet prior
to reaching the selected altitude,
flash twice upon reaching the
selected altitude, and flash four
times when deviating above or
below the selected altitude by
more than the warning selected.
Additionally, the altitude-alerting
GPAAS in aircraft that do not have
an altitude pre-selector. The
GPAAS will announce "Altitude,
situations. In those aircraft with an
alerting is incorporated with that
Navigation (VNAV) feature that allows an ascent or
descent path to be programmed and then provides
advisory altitudes to fly to arrive at a waypoint at a
specified altitude. The NAV 4 page is used to program
1. Select the NAV 4 page on either
side of the screen. The NAV 4
page can be selected either by
using the outer and inner knobs or
by pressing the altitude button to
bring up the NAV 4 page on the
right and the Altitude page on the
automatically displayed on the NAV 4 page. Prior to
programming a VNAV operation, the top of the page
displays VNV INACTV.