Garmin GTS 855 - Manual (Page 15)

11 190-00587-02 Rev. A Garmin GTS 8XX Series Traffic Advisory System
GTS 8XX Series Sensitivity Level
The GTS 8XX Series issues Traffic Advisories according to the current Sensitivity
Level (SL). To prevent nuisance alerts near airports, the GTS 8XX Series has two
sensitivity levels available, Sensitivity Level A (SLA) and Sensitivity Level B (SLB).
Refer to Table 5 for Sensitivity Level definitions. SLA is used to reduce sensitivity
levels in airport environment and avoid nuisance traffic alerts.
The logic for choosing the sensitivity level is based on aircraft configura-
tion. SLA is determined according the following order:
1. Ownship is below 2,000 feet AGL (if equipped with a radio altimeter)
2. Landing gear is extended (no radio altimeter is installed on retractable gear
aircraft)
3. Ground speed is below 120 knots (no radio altimeter installed in a fixed-gear
aircraft)
The GTS 8XX Series will remain in SLB at all other times. In the event a
fixed-gear aircraft is not equipped with a radio altimeter and ground speed is not
available, the GTS 8XX Series will remain in SLB at all times.
Note: If the GTS 8XX Series is interfaced to a radio altimeter, or if the gear/
wheel is configured as fixed, the system will ignore the GEAR DOWN AND
LOCKED discrete input.
In both SLA and SLB, audio alerts are suppressed only under the following
conditions:
1. If radio altimeter is installed and own altitude is less than 400 feet AGL.
2. If no radio altimeter is installed in a retractable gear aircraft and gear is
extended.