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Aviation Alerts and Advisories

Service Alert 050523-02: GPS 500/GNS 530 TAWS Navigation Alert

STATEMENT OF REVISION FOR -02

Data required to completely define the affected ILS approaches has been incorporated into the Jeppesen Navigation Database. As such, this alert does not apply when using Jeppesen Data cycle 0506 or later.

This alert supersedes all previous versions of Service Alert 050523.

AFFECTED PRODUCTS

Garmin 500 series TAWS units with Jeppesen Data cycle 0505 and prior

IMMEDIATE ACTION REQUIRED

The pilot should inhibit TAWS when flying the listed Canadian ILS approaches.

DESCRIPTION OF ISSUE

The 500 series TAWS units with Jeppesen Data cycle 0505 (and prior) issue nuisance PDA (Premature Descent Alerts) when flying ILS approaches at the Canadian locations listed in the AFFECTED LOCATIONS section of this bulletin.

The issue occurs because data needed by the TAWS algorithm is not included in the Jeppesen Database (data cycle 0505 and prior) for these specific ILS approaches. The missing information results in PDA alerts from the Final Approach Fix (FAF) to the runway.

RESOLUTION

If using a 500 series TAWS unit with Jeppesen Data cycle 0505 or prior data cycle, the pilot should inhibit the TAWS function at the FAF waypoint when flying one of the following identified Canadian ILS approaches. Jeppesen Data cycle 0506 (effective 06/09/05) of the Jeppesen Navigation Database includes adjustments to remove this operational issue. This solution eliminates the nuisance PDA alerts for the ILS approaches at the airports in following list. 

To inhibit the TAWS function, select the TAWS page, press the MENU button, and select the “Inhibit Terrain?” option. For installations with an external annunciator, press the “INHB TERR” button.

AFFECTED LOCATIONS

Download SA0523-02