Garmin GNC 300 Pilot's Manual page 67

SUA Settings Page
All SUA alert messages except for prohibited areas may be turned on or off
through the GNC 300' s unit settings options, found under the MSG key (see Section
7). The GNC 300 will also automatically turn off SUA alerts during approach opera-
tions (see Section 6). Alerts for prohibited areas will always be displayed, regardless of
unit settings or operating mode. SUA alerts may be turned off so the pilot can avoid
continuous alerts in areas with extensive special use airspace.
Important: Turning off the SUA alerts only stops the display of SUA messages.
Any applicable SUA alert pages will still be available from the NRST key.
The GNC 300 also features an altitude buffer which may be set to provide a
greater level of protection from penetrating an SUA. By specifying an altitude in the
buffer, you can effectively stretch an SUA' s altitude boundaries in both directions. This
allows the pilot to add an extra margin of prevention around controlled or restricted
airspace. For instructions on setting the altitude buffer, see Section 7.
APPENDIX A
NRST KEY SECTION
4
Unit Settings List
Special Use Airspace
Altitude buffer set at 500 feet.
57