AIM
11/3/22
fighter will be more difficult to see on primary radar
than a large commercial jet or military bomber. Here
again, the use of transponder or ADS
−
B equipment is
invaluable. In addition, all FAA ATC facilities
display automatically reported altitude information
to the controller from appropriately equipped aircraft.
(f)
At some locations within the ATC en route
environment, secondary
−
radar
−
only (no primary
radar) gap filler radar systems are used to give lower
altitude radar coverage between two larger radar
systems, each of which provides both primary and
secondary radar coverage. ADS
−
B serves this same
role, supplementing both primary and secondary
radar. In those geographical areas served by
secondary radar only or ADS
−
B, aircraft without
either transponders or ADS
−
B equipment cannot be
provided with radar service. Additionally, transpon-
der or ADS
−
B equipped aircraft cannot be provided
with radar advisories concerning primary targets and
ATC radar
−
derived weather.
REFERENCE
−
Pilot/Controller Glossary Term
−
Radar.
(g)
With regard to air traffic radar reception,
wind turbines generally do not affect the quality of air
traffic surveillance radar returns for transponder and
ADS
−
B Out equipped aircraft. Air traffic interfer-
ence issues apply to the search radar and
Non
−
Transponder/Non
−
ADS
−
B Out equipped air-
craft.
NOTE
−
Generally, one or two wind turbines don’t present a
significant radar reception loss. A rule of thumb is three (3)
or more turbines constitute a wind turbine farm and thus
negatively affect the search radar product.
(1)
Detection loss in the area of a wind
turbine farm is substantial. In extreme circumstances,
this can extend for more than 1.0 nautical mile (NM)
horizontally around the nearest turbine and at all
altitudes above the wind turbine farm. (See
FIG 4
−
5
−
2.)
FIG 4
−
5
−
2
Wind Turbine Farm Area of Potential Interference
NOTE
−
All aircraft should comply with 14 CFR §91.119(c)
“
…
aircraft may not be operated closer than 500 feet to any
person, vessel, vehicle, or structure.”
(2)
To avoid interference Non
−
Transpon-
der/Non
−
ADS
−
B Out equipped aircraft should avoid
flight within 1.0 NM horizontally, at all altitudes,
from the wind turbine farms.
(3)
Because detection loss near and above
wind turbine farms for search
−
only targets causes
dropped tracks, erroneous tracks, and can result in
loss of separation, it is imperative that Non
−
Transponder/Non
−
ADS
−
B Out equipped aircraft
operate at the proper VFR altitudes per hemispheric
rule and utilize see
−
and
−
avoid techniques.
(4)
Pilots should be aware that air traffic
controllers cannot provide separation from Non
−
Transponder/Non
−
ADS
−
B Out equipped aircraft in
the vicinity of wind turbine farms. See
−
and
−
avoid is
the pilot’s responsibility, as these non
−
equipped
aircraft may not appear on radar and will not appear
on the Traffic Information Services
−
Broadcast
(TIS
−
B).
4
−
5
−
2
Surveillance Systems