Garmin G1000 NXi Reference Manual page 161

Altitude-Critical Modes (ALT, GS, GP, GA, FLC)
As the aircraft slows, within 5 to 10 seconds from reaching stall warning, an
aural "AIRSPEED" alert will sound. If the aircraft decelerates to stall warning, the
lateral and vertical flight director modes will change from active to armed, and the
autopilot will provide input causing the aircraft to pitch down and the wings to level.
An aural "AIRSPEED" alert will sound every five seconds and a red "UNDERSPEED
PROTECT ACTIVE" annunciation will appear to the right of the vertical speed
indicator. The pitch down force will continue until the aircraft reaches a pitch
attitude at which IAS equals the IAS at which stall warning turns off, plus two knots.
USP Airspeeds - Altitude Critical
Modes
MINSPD Alert Appears
Altitude Critical USP Activation
Non-Altitude Critical Modes (VS, VNAV, PIT, LVL)
When the airspeed trend vector reaches a predetermined airspeed, a single aural
"AIRSPEED" will sound, alerting the pilot to the impending underspeed condition.
If the aircraft decelerates to an IAS below the minimum commandable autopilot
airspeed, a red "UNDERSPEED PROTECT ACTIVE" annunciation will appear to the
right of the vertical speed indicator. The vertical flight director mode will change from
active to armed, and the autopilot will cause the aircraft to pitch down until reaching
a pitch attitude at which IAS equals the minimum commandable autopilot airspeed.
When airspeed increases (as a result of adding power/thrust) to an
IAS above the minimum commandable autopilot airspeed, the autopilot
will cause the aircraft to pitch up until recapturing the vertical reference.
The vertical flight director mode will change from armed to active.
190-02178-02 Rev. A
All Flap
USP Activation - Altitude Critical Modes
Garmin G1000 NXi Cockpit Reference Guide for the Cessna NAV III
172 182
KIAS KIAS
All Flap
60 61
60 Stall Warning
AFCS
206
KIAS
All Flap
61
Stall Warning
135