Cockpit Reference Guide

Garmin G1000 Cockpit Reference Guide for the Cessna Nav III
10-13
SECTION 10 – HAZARD
AVOIDANCE
calculated to come within minimum clearance altitudes
in the following table.
Phase of Flight Level Flight Descending
Enroute 700 ft. 500 ft.
Terminal 350 ft. 300 ft.
Approach 150 ft. 100 ft.
Departure 100 ft. 100 ft.
During the final approach phase of flight, RTC/ROC/
ITI/IOI alerts are automatically inhibited when the aircraft
is below 200 feet AGL while within 0.5 nm of the approach
runway or is below 125 feet AGL while within 1 nm of the
runway.
Premature Descent Alert (PDA)
A Premature Descent Alert is issued when the system
detects that the aircraft is significantly below the normal
approach path to a runway. The PDA alert mode functions
only during descent to land.
PDA alerting begins when the aircraft is within 15 nm
of the destination airport and ends when the aircraft is
either 0.5 nm from the runway threshold OR is at an alti-
tude of 125 feet AGL while within 1 nm of the threshold.
During the final descent, algorithms will set a threshold
for alerting based on speed, distance, and other param-
eters.
Figure 10-20 PDA Alerting
Excessive Descent Rate Alert (EDR)
The purpose of the Excessive Descent Rate alert is to
provide suitable alerts when the aircraft is determined
to be closing (descending) upon terrain at an excessive
speed. Figure 10-21 displays the correlation between
height above terrain and descent rate, resulting in the two
EDR alerts. EDR alerts have two levels of severity, caution
(sink rate) and warning (pull-up).
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
2000 4000 6000 8000 10000 12000
"PULL UP""
P
U
L
L
U
P
"
"
S
I
N
K
R
A
T
E
"
Descent Rate (FPM)
Height Above Terrain (Feet)
Figure 10-21 Excessive Descent Rate
Negative Climb Rate After Takeoff
Alert (NCR)
The purpose of the Negative Climb Rate After Takeoff
alert is to provide suitable alerts to the pilot when the
system determines that the aircraft is losing altitude
(closing upon terrain) after takeoff. The aural message
“Don’t Sink” is given for NCR alerts, accompanied by an
annunciation and a pop-up terrain alert on the display.