Garmin International
1200 E. 151
st
Street Olathe, KS 66062
USA
ROTORCRAFT FLIGHT MANUAL SUPPLEMENT
for STC SR02123SE
GARMIN GDL 84H/88H ADS-B TRANSCEIVER
190-01310-J2 Rev. 1
Page 15 of 16
Traffic Sources and Alerting
The GDL 84H/88H is capable of receiving ADS-B, ADS-R, and TIS-B traffic
reports in order to track traffic around the rotorcraft and provide alerts to the
flight crew to aid in visual acquisition and avoidance.
Traffic alerting is provided via a visual annunciator and audio callouts for these
alerts.
Rotorcraft which have a Radar Altimeter OR GNS or GTN display interfaced to
the GDL 84H/88H will truncate traffic aural alerts to not include bearing,
distance, and relative altitude information when less than 200 ft above the
surface. Additionally, the GDL 84H/88H will reduce the protected volume
around these rotorcraft when operating below 200 ft above the surface and less
than 60 kts groundspeed to minimize nuisance alerts in the airport area while
still providing traffic alerts on other eligible ADS-B OUT equipped aircraft.
Aircraft which are ADS-B participants transmitting on the 1090 MHz band do
not transmit altitude while in the on ground state and thus will not generate
traffic alerts until becoming airborne.
Due to some aircraft not being required to equip for ADS-B Out, as well as the
nature of TIS-B, its service volumes, not all traffic will be tracked by the GDL
84H/88H. This is much like an active traffic system which does not track non-
transponder equipped aircraft. The flight crew must use “see and avoid”
procedures to visually acquire and avoid other aircraft.
On Scene Mode (OSM)
Rotorcraft which have a GTN display interfaced to the GDL 88H have the
ability to use On Scene Mode (OSM). OSM reduces the protected volume
around the rotorcraft for alerts that would be produced by other ADS-B
equipped helicopters. OSM must turned ON and OFF by the pilot using the
controls in the MENU of the GTN’s traffic page and is intended to be used when
intentionally operating in close proximity to other helicopters for activities such
as ENG. OSM does not affect the protected volume for other airplanes or non-
ADS-B equipped helicopters.
Interfaced Active Traffic System (Optional, GDL 88H Only with GTN)
When an active traffic system is interfaced with a GDL 88H, the GDL 88H
receives traffic from the active traffic system and attempts to correlate – or
match – this traffic with ADS-B traffic the GDL 88H has received and is already
tracking. When a correlation is made, the active traffic system or ADS-B target
with the most accurate information is displayed to the flight crew. Any active
Summary of Contents for GDL 84H
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