Alert Zones - FLARM FUSION PowerFLARM User And Maintenance Manual

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In addition to predicted impacts, obstacle collision warnings are also issued when
a sudden change of flight path could lead to an obstacle collision. This includes
flying parallel to a line obstacle or turning around the end of a line obstacle. At the
same time, obstacle collision warnings are not issued when circling (e.g. gliders
thermalling) close to a line obstacle. The effect is visualized in the graphic below,
the red dashed line illustrating where collision warnings are issued.
For obstacle collision warnings, no relative bearing or altitude difference is
indicated since this is always along the own predicted flight path.
6.4

Alert Zones

Skydiver drop zones and UAV operations areas may be equipped with FLARM Alert
Zone generators. These consist of FLARM-based ground stations that broadcast a
cylinder-formed airspace around the affected area. Both the ground station
operator and pilots flying in the cylinder are alerted when an aircraft enters the
airspace.
The FLARM system onboard the aircraft will issue a warning for 4 seconds every
12 seconds while flying inside the zone. After the first 3 warnings, while still inside
the zone, the warning will be repeated only every 60 seconds.
FLARM Compatible displays using FLARM protocol version 7 or higher will indicate
the Alert Zone warning in a unique way. Other displays will indicate the warning
as an obstacle collision warning, but with the timing of the warning still according
to the schedule described above.
POWERFLARM
FUSION USER AND
MAINTENANCE
MANUAL
Date: 2020-11-10
Version: 1.0
Page: 31 of 49
Document Number:
FTD-078