Garmin G900X Pilot's Manual page 365

PREMATURE DESCENT ALERTING
A Premature Descent Alert (PDA) is issued when the system detects that the aircraft is significantly
below the normal approach path to a runway (Figure 6-53).
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 altitude of 125 feet AGL while within 1.0 nm of the
threshold. During the final descent, algorithms will set a threshold for alerting based on speed, distance, and
other parameters.
PDA and FLTA aural and visual alerts can be manually inhibited. Discretion should be used when inhibiting
TAWS and the system should be enable when appropriate. When TAWS is inhibited, the alert annunciation
'TAWS INHB' is shown on the PFD and MFD (Figure 6-54).
Inhibiting/enabling TAWS alerting:
1) Select the TAWS Page.
2) Press the MENU Key.
3) Select 'Inhibit TAWS' or 'Enable TAWS' (choice dependent on current state) and press the ENT Key.
If TAWS alerts are inhibited when the Final Approach Fix is the active waypoint in a GPS WAAS approach,
a 'LOW ALT' annunciation may appear on the PFD next to the Altimeter if the current aircraft altitude is at
least 164 feet below the prescribed altitude at the Final Approach Fix. See the Flight Instruments Section for
details.
190-00726-00 Rev. A
700
600
500
400
300
200
100
Runway
1 2 3 4
Threshold
Distance From Destination Airport (nm)
Figure 6-53 PDA Alerting Threshold
Figure 6-54 TAWS Alerting Disabled
(TAWS Inhibited) Annunciation
Garmin G900X Pilot's Guide
PDA Alerting Area PDA Alerting Area
5 6 7 8 9 10
HAZARD AVOIDANCE
11 12 13 14 15
6-39