Garmin Columbia 350/400 manual Taws Inhibit, Manual System Test, Premature Descent Alert PDA

SECTION 10 – HAZARD

AVOIDANCE

TAWS Inhibit

Flying VFR into an area where unique terrain exists could cause the system to annunciate a nuisance alert. When TAWS is inhibited, only FLTA and PDA alerts are disabled.

Inhibit TAWS:

1)While the TAWS Page is displayed, press the MENU Key.

2)Turn the small FMS Knob to select‘Inhibit TAWS’.

3)Press the ENT Key.

Enable TAWS:

1)While the TAWS Page is displayed, press the MENU Key.

2)Turn the small FMS Knob to select ‘Enable TAWS’.

3)Press the ENT Key.

Manual System Test

A system test is automatically performed at power-up. After sucessful completion of the test, “TAWS System Test, OK” will be heard.

The system test may also be initiated manually, but only when the aircraft is on the ground. To manually verify proper operation of the aural and visual annunciations of the system, perform the following steps.

1)While the TAWS Page is displayed, press the MENU Key.

2)Turn the small FMS Knob to select ‘Test TAWS’.

3)Press the ENT Key. During the test ‘TAWS TEST’ is displayed in the center of the TAWS Page.

When all is in working order, “TAWS System Test, OK” will be heard.

Forward Looking Terrain Avoidance (FLTA)

The Forward Looking Terrain Avoidance alert is composed of two sub-functions:

Reduced Required Terrain Clearance (RTC) and Reduced Required Obstacle Clearance (ROC)

This provides alerts when the aircraft flight path is above terrain and/or obstacles, yet is projected to come within minimum clearance values outlined in the following table. When an RTC or ROC alert is issued, a potential impact point is displayed on the TAWS Page as a yellow or red ‘X’.

Imminent Terrain Impact (ITI) and Imminent Obstacle Impact (IOI)

This provides alerts when the aircraft is below the elevation of terrain in the aircraft’s projected path. ITI and IOI alerts are accompanied by a potential impact point displayed on the TAWS Page as a yellow or red ‘X’. The alert is given when the projected vertical flight path is 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

10-12 Garmin G1000 Cockpit Reference Guide for the Columbia 350/400