Honeywell KLN 900s Pilot's Manual page 67

CAUTION: Failure to keep the altimeter baro setting
updated will result in inaccurate special use airspace
alerting. If this feature is used, it is a good idea to
update the altimeter baro setting on the ALT page
each time you make a change to an aircraft's altime-
ter setting.
NOTE: If there is no altitude input to the KLN 900, all alti-
tudes will be regarded as being within the boundary of the
SUA area.
Only the outer lateral boundaries are stored for Class B,
Class C, CTA, and TMA airspace. These SUA areas are
SPECIAL USE AIRSPACE ALERT
2 MILES
Figure 3-128
3-40
stored as "cylinders" of airspace so all altitudes below the
upper limit of these areas are considered to be in the
SUA.
The message prompt for a special use airspace alert will
occur when the aircraft's position is at a point such that a
projection of the aircraft's existing track over the ground is
approximately 10 minutes from penetrating the outer
boundary of one of these areas. It will also occur if the
aircraft is within approximately two nautical miles of one
of these areas even if the aircraft's projected track over
the ground won't actually penetrate the SUA area (figure
3-128). If one of the SUA areas is penetrated, another
message will state: INSIDE SPC USE AIRSPACE.
10 MIN
Rev 2