Operational States
While a missing or invalid SafeTaxi® Database will reduce functionality, SurfaceWatch™ will remain operational. All SurfaceWatch alerting is based on the Navigation Database. The SurfaceWatch Information Box will show only ‘On’ or ‘Approaching’ runway information if the SafeTaxi Database is missing or invalid or if the airport does not have SafeTaxi diagrams.
SurfaceWatch has four distance operational states: Normal, Fail, Inhibited, and Disabled.
|
Alert |
Description |
|---|---|
|
SFCWTC FAIL (One or more inputs invalid) |
The GPS or WAAS position could be invalid, or is insufficient due to RAIM position warning, loss of integrity, or the GPS horizontal protection level exceeds the LNAV/VNAV horizontal alert limit (556.0 meters). Heading Input could be invalid. |
|
SFCWTC INHIB (SurfaceWatch inhibited) |
SurfaceWatch has been inhibited by the pilot. Aural and visual alerts are inhibited. Functionality will automatically reset on a system restart. |
|
SurfaceWatch Disabled: Too far north/south |
Issued when the aircraft is positioned north of N 87° latitude or south of S 87° latitude. |
|
Runway Data Not Available: Inhibit SurfaceWatch |
Not enough information is available for the active runway, SurfaceWatch will issue nuisance alerts if not inhibited. See Enabling/Disabling SurfaceWatch Alerts (When Enabled):. Some airports within the Navigation database do not have surveyed runway position data for all runways at the airport (e.g., soft surface runways, turf, gravel, etc.). In these cases, SurfaceWatch may either issue alerts, or may not provide alerts, or may not be able to display complete Information Box data at that airport. |
The following image displays the ‘Messages’ Window. The previously discussed annunciations will populate the ‘Messages’ Window as applicable. In the below image, 'SFCWTC INHIB' is annunciated.
