GPS 400 Pilot’s Guide and Reference
190-00140-60 Rev. E
7-9
SECTION 7
NRST PAGES
7.9 NEAREST AIRSPACE PAGE
The last page in the NRST group, the Nearest Airspace
Page (Figure 7-21) alerts the pilot to as many as nine
controlled or special use airspaces near or in the flight
path. Alerts are provided according to the following
conditions:
• If the projected course will take the aircraft inside
an airspace within the next ten minutes, the alert
message ‘Airspace ahead -- less than 10 minutes’
appears (Figure 7-19). The Nearest Airspace Page
shows the airspace as ‘Ahead’.
Figure 7-19 Airspace Messages
• If the aircraft is within two nautical miles of
an airspace and the current course will take
the aircraft inside, the message ‘Airspace near
and ahead’ appears (Figure 7-19). The Nearest
Airspace Page shows ‘Within 2nm of airspace’.
• If the aircraft is within two nautical miles of an
airspace and the current course will not take the
aircraft inside, the message ‘Near airspace less
than 2nm’ appears. The Nearest Airspace Page
shows the airspace as ‘Ahead < 2nm’.
• If the aircraft has entered an airspace, the message
‘Inside Airspace’ appears (Figure 7-20). The
Nearest Airspace Page shows ‘Inside of airspace’.
Figure 7-20 Airspace Messages
Note that the airspace alerts are based on three-
dimensional data (latitude, longitude, and altitude) to
avoid nuisance alerts. The alert boundaries for controlled
airspace are also sectorized to provide complete
information on any nearby airspace. Once one of the
described conditions exists, the message annunciator
flashes, alerting the pilot of an airspace message.
Viewing an airspace alert message:
1) When the message annunciator above the
MSG
Key flashes, press the
MSG
Key.
2) Press the
MSG
Key again to return to the
previous page.
