JP 3-50 National Search and Rescue Manual Vol I - US Navy

continental U.S. and at offshore locations, record primary and
secondary radar data through a series of long range radar
sited via NAS computers. Recorded data is retained for a
period of 15 days. Data can be extracted in a hard copy form.
In some cases, data can be viewed on a CRT providing a more
rapid form of review.
b. Automatic Radar Terminal System 3 (ARTSIII). The FAA
operates 62 Terminal Radar Approach Control (TRACON)
facilities equipped with the ARTSIII tracking computer.
ARTSIII systems generally record both primary and secondary
radar. Recorded data is retained for 15 days and is extracted
in a hard copy format.
4. VHF direction-finding nets, covering the frequency bands of
118-156 MHz. These nets, composed of DF sites at airports and
FSSs, are supplemented by military airport DF sites, and
provide almost complete coverage of the continental United
States and Alaska. DF sites are also located in Puerto Rico,
the Virgin Islands, the Hawaiian Islands, and Wake Island.
a. The FAA operates approximately 27 ARTCCs for all
areas where the United States provides ATC services. Each
ARTCC is responsible for maintaining a VHF DF net within its
area of control, and acts as the net control station. ARTCCs
may pass net control to any DF station within their net. VHF
DF nets locate aircraft that are lost or experiencing an
emergency and then vector them to the nearest suitable
airport. The net can also vector SAR aircraft to the same
line of bearing as the distressed aircraft, help the SAR
aircraft to maintain the same bearing line, and aid in
completing an intercept.
b. A DF net is alerted any time a pilot admits being
lost or declares an emergency, and may be alerted via any
ARTCC, FSS, FAA tower, military tower, or RCC. When an RCC
alerts a net, it should provide the following:
(1) Call sign or other identification of the distressed
aircraft.
(2) Frequency and type of transmission (MCW or voice)
being used by the distressed aircraft.
(3) Call sign or other identification of intercepting
aircraft.
(4) Whether the distressed aircraft is or is not
transmitting at the time of the call, or when it is
next scheduled to transmit.
(5) Nature of the emergency, including emergency phase
(Distress, Alert, or Uncertainty).