The 1970's Tactical Air Control System (TACS)

Note: In the early 1970's 407L equipped units used the TPS-43 radar. The majority of the ANG units mainly used the MPS-11 surveillance radar, and the TPS-40 height finder radar. By the end of the 1970's, the 407L and ANG units had all converted to the TPS-43E surveillance radar. The following information will be in reference to the TPS-43E, 407L type units.

Air Force Component Command Post (AFCCP)
An Air Force Group

Tactical air control center (TACC)
The principal air operations installation from which all aircraft and air warning functions of tactical air operations are controlled. Usually a Squadron.

Control  and Reporting  Center  (CRC).  The CRC provided ACW radar surveillance and identification of aircraft (IFF/SIF) within its sector. It coordinated and controlled the ACW elements of the CRP and FACP and provided air situation information to the TACC. It also performed the function of air traffic regulation (ATR) and was the air traffic regulation center (ATRC) within a TACS. Usually a Squadron. Typical Layout

The CRC was designed to be deployed in support of minimum, medium, and maximum tactical Air Force levels. This means an initial deployment into an active situation could deploy a minimum CRC. When the battle situation stabilized, or the volume of direct air support increased, additional equipment was joined to the CRC to increase its capacity. The expansion of a CRC from a minimum to a maximum configuration was reflected by a proportional increase of personnel, equipment, channels of communications and support facilities.

Mission. A CRC was responsible for surveillance and identification of all air traffic in a TACS area. This included navigational assistance, air traffic regulation, and coordination of air traffic control with other agencies such as FAA. The supervision of surveillance and control activities of all CRPs and FACPs within the TACS was also a CRC function. When necessary, the CRC issued scramble orders and assigned aircraft and specific weapons on both offensive and defensive missions. The CRC also forwarded the status and evaluation of the air situation to the TACC or could perform the TACC functions, if necessary.

In order to perform these responsibilities, the CRC was divided into three primary operational sections: (1) Surveillance, (2) weapons directing and (3) Air Traffic Regulation Center (ATRC).

Surveillance section. The basic functions of this section were to detect, track, and identify aircraft and to record, display, and provide air surveillance data. The surveillance section also received, records, and provided the status of weapons, air bases, air missions, weather, and equipment.

Weapons direction section. The weapons direction section implemented and directed the use of air weapons to specific tasks and exercised close supervision of offensive and defensive missions. It also provided flight following and navigational guidance to aircraft under the weapons controller's jurisdiction for offensive, interdiction, tactical airlift, reconnaissance, air refueling, and close air support missions.

Air traffic regulation center section. The airspace control function, performed by the ATRC section, maintained situation data on friendly air activity and provided the necessary coordination, integration, and regulation of air traffic within the TACS area of responsibility. Radar flight following and control of aircraft were also performed by ATRC to ensure reasonable separation of essential missions and to avoid conflict with other aircraft.

Equipment. A CRC could have been deployed and erected in one of three basic configurations or sizes as well as several variations of them: minimum, medium, and maximum. These configurations were not restrictive; however, each provided a starting point from which a staff planner could tailor the configuration best adapted to the tactical situation.

CRC was the highest element of a TACS that had radar capabilities. Also required was a means of displaying, recording, and providing radar data, both automatically and/or manually.

The CRC contained a surveillance radar, height finding capacity (either through the use of a “3-D” or separate height finder radar), and an operations central.  The operations central could be either the 407L  TSQ-91 type, or the manual type used by some Air National Guard (ANG) units.  The ANG manual units did not have any computer capability.
The operation of the radar set, in conjunction with radar support equipment contained in the operations central, provided the CRC with the capabilities described next:

Three-dimensional radar coverage (range, azimuth, and elevation).

Positive identification of aircraft by means of identification friend or foe/selective identification feature (IFF/SIF) ancillary radar equipment.

Accurate radar return data on moving targets through use of moving target indicator (MTI) and associated electronics.

Automatic or manual recognition of jamming signals by means of jamming analysis transmission selection (JATS). This capability included automatic retuning to an un-jammed frequency (TPS-43 equipped).

Display of radar video data and console-operator-generated symbols on planned position indicator (PPI) and auxiliary readout (ARO) displays (407L only).

Mapping of radar video data by means of video mapper and associated mapper electronics.

Computer-assisted radar operations (with a data processing module only)

Transmission and reception of radar track data via automatic data link (ADL) channels (407L equipped units).

TPS-43E 3-D Surveillance Radar
The AN/TPS-43E was an air-transportable, three-dimensional radar, capable of detecting targets from a minimum range of 1 nautical mile (nmi) to a maximum range of 240 nmi. In addition, the radar provides 360° coverage to pick up aircraft flying at altitudes up to 100,000 feet. The radar is made up of a jamming analysis transmission selection, moving target indicator, and a signal processor to evaluate, compare, and store received target information. The radar also provides IFF/SIF interrogation and decoding equipment for positive aircraft identification

AN/TSQ-91 Operations Central
The operations central, TSQ-91 consists of transportable, modular equipment which may be assembled into any one of the three operating location configurations (minimum, medium, and maximum). ANG units used a variety of Operations Centrals to house their manual equipment in. They included the S-80 Operations Shelter, the S-80A Operations Shelter, and the TSQ-92 Operations Shelter.

AN/TRC-97A Radio Set
The AN/TRC-97A (fig. 1-6) is a transportable radio set which provides primary microwave communication with other ground-based units. The radio set is capable of simultaneous two-way communications on 24 channels. The AN/TRC-97 can also be adapted to provide teletype (TTY) and data link transmissions. Data link is the communications method that the computers; use to exchange information with each other.

AN/TRC-87 Radio Set
The AN/TRC-87 radio set was a two-way ultra-high frequency (UHF) radio which provided the primary ground-to-air voice communications at the CRC. Each radio set provided five transmitter/receiver channels. A CRC had three AN/TRC-87 radio sets.

AN/TRC-60 Radio Set
The TSC-60 was a transportable, shelter-mounted unit that provided HF/SSB terminals for point-to-point and ground-to-air communications. A single shelter housed two transmitters, two receivers, and associated equipment which provided simplex and duplex voice, TTY, and digital data communications capabilities. The TSC-60 provided 1 kilowatt (kW) of output power. The TSC-60 was used to provide backup channels for the TRC-97A when needed.

AN/TTC-30 Electronic Telephone Central Office
The TTC-30 was a transportable shelter-mounted electronic telephone central office. The TTC-30 provided automatic call processing functions for establishing connections requested by any subscriber

A/E24U-8 Generator Set
The A/E24U-8 (fig. 1-7) was a 120-kW power source consisting of two EMU-30 gas-turbine driven, 60-kW generators. The power source was mounted on a transport pallet to hold the generators, a power distribution panel, control panels, a power regulating and control system, and a fuel system. Eight 50-foot lengths of power distribution cable were stored on reels fastened at the rear of the pallet.