Section 5. Terminal Radar

10-5-1. SHUTDOWN OF PAR ANTENNAS

When PAR equipment is not required for ATC controller training, maintenance, or other use, shut down the antenna. Keep the main power supply and the high voltage system energized to permit immediate restoration of PAR equipment for operational use.

10-5-2. RADAR DISPLAY INDICATORS

a. Radar approach and departure control functions will normally be conducted from a TRACON. Either direct view or a CTRD may be used. These functions may be performed from the tower cab if:

b. Not more than two radar operating positions are required and CTRDs are used on a permanent basis.

c. More than two operating positions are required and CTRDs are installed on an interim basis pending the establishment of a TRACON.

d. On a temporary basis if other than CTRDs are installed.

e. Consider the following if scan conversion type bright display equipment is used:

f. A standard bright display installation consists of one operational and one standby scan conversion unit. The range and centering selected for the master bright display will be the same on all slaved bright display indicators.

g. If the particular radar operating positions concerned require a capability for individual beacon decoding, each bright display position will require a separate scan conversion unit.

h. That a determination must be made if surveillance approach capability would be lost using only scan conversion bright display indicators. If the determination is that it would be lost, at least one direct view indicator must be retained.

i. VFR Radar Advisory Service functions will normally be conducted from the TRACON.

j. A CTRD installed in the tower cab for LC use must be positioned where it can be conveniently viewed from the local controller's normal sitting or standing position.

k. PAR functions will normally be conducted in a TRACON.

l. ASDE indicators must be placed in the tower cab so as to serve the LC and GC positions.

m. The CTRD may be used for any terminal radar function.

n. The 12-inch or larger display monitor may be used in lieu of a CTRD when authorized by the region and the display is certified by airway facilities. Any display monitor less than 12 inches must not be used for ATC separation purposes. It is primarily to provide alphanumeric readout capability to the CD/FD position at locations where that position has keyboard access to an ATTS.

10-5-3. FUNCTIONAL USE OF CERTIFIED TOWER RADAR DISPLAYS

a. At towers combined with full radar approach control facilities where controllers rotate between the approach control and the tower, CTRDs may be used by local controllers for any terminal radar function provided their ability to satisfy FAA's air traffic responsibilities regarding the aircraft operating on the runways or within the surface area for which the tower has responsibility is not impaired. The conditions and/or limitations for the radar usage must be specified by a facility directive.

b. At towers combined with full radar approach control facilities where controllers do not rotate between the approach control and the tower, or at towers not combined with full radar approach control facilities, CTRDs may be used by local controllers for the following functions:

1. To determine an aircraft's identification, exact location, or spatial relationship to other aircraft.

NOTE-
This authorization does not alter visual separation procedures. When employing visual separation, the provisions of FAAO JO 7110.65, Air Traffic Control, para 7-2-1, Visual Separation, apply.

2. To provide aircraft with radar traffic advisories.

3. To provide a direction or suggested headings to VFR aircraft as a method for radar identification or as an advisory aid to navigation.

4. To provide information and instructions to aircraft operating within the surface area for which the tower has responsibility.

5. To ensure separation between successive departures, between arrivals and departures, and between overflights and departures within the surface area for which the tower has responsibility provided:

(a) There is no airspace delegated to the tower;

(b) The local controllers have radar training and certification commensurate with their radar duties;

(c) A LOA, approved by the respective Terminal Operations Service Area Office, exists with the IFR facility having control jurisdiction which authorizes the specific radar function and prescribes the procedures to be used;

(d) The LOA prescribes the process for a transition to nonradar procedures or the suspension of separation authority in the event of a radar outage;

(e) The procedures for giving and receiving radar handoffs or pointouts do not impair the local controller's ability to satisfy FAA's air traffic responsibilities regarding the aircraft operating on the runways or within the surface area for which the tower has responsibility; and

(f) The procedures for ensuring radar separation do not require the tower to provide radar vectors.

c. At locations where uncertified tower displays are in use, the services and phraseology set forth in FAAO JO 7110.65, Air Traffic Control, Chapter 5, Radar, must not be utilized. Uncertified displays must be used only as an aid to assist controllers in visually locating aircraft or in determining their spatial relationship to known geographical points.

d. Operational applications of tower radar displays other than those outlined in subparas a and b, and/or the delegation of airspace to a tower require a staff study as prescribed in para 2-1-15, Authorization for Separation Services by Towers.

10-5-4. ASR PERFORMANCE CHECKS

Each radar controller is responsible for determining on a day­to­day basis if the quality of their radar display and video display accuracy is satisfactory for ATC purposes.

a. At locations using digital terminal automation systems (DTAS), such as STARS, MEARTS, and ARTS III­E, daily ASR performance checks are not required. DTAS conducts continuous self monitoring checks for performance and alignment.

b. At facilities that do not use a DTAS, radar quality and performance is determined by comparing identified targets against data obtained during the commissioning flight check or through minimum performance criteria determined jointly by air traffic and Technical Operations personnel. Radar controllers must be familiar with commissioning flight check and minimum performance data. Air traffic managers must make this information available to the controllers. Aircraft selected for these daily checks should be small aircraft similar in size to those used in the commissioning flight checks.

c. The daily radar performance check must be a part of the routine checks of equipment. (See para 4­6­5, Preparation of FAA Form 7230­4). The check must be accomplished once each watch. It is recognized that on some watches this check may not be accomplished because of the lack of traffic.

REFERENCE-
FAAO JO 7110.65, Para 5­1­2, Alignment Check.

10-5-5. DEFICIENCIES IN SYSTEM

Note deficiencies in the radar system on FAA Form7230-4. Reconcile them as follows:

a. After consultation with the Technical Operations representative, the terminal air traffic manager or his/her representative must decide if this radar system is usable. Consider atmospheric or other phenomena that may temporarily affect radar performance.

b. Certification by Technical Operations personnel that a malfunction has been corrected must be entered on FAA Form 7230-4.

NOTE-
Technical Operations representatives may ground check the equipment to determine if the radar system is operating satisfactorily or request a special flight check.

10-5-6. RADAR TOLERANCES

ASR systems must conform to the following tolerances for radar performance checks:

a. Coverage: A usable target return (one which is not missed on more than two consecutive scans) will be maintained along the entire airway/route or arrival/departure control routes for which radar service is provided. Tracking accuracy along these routes will be within the fix/map accuracy in subpara b. Radar services for arrival or departure routes are considered to exist between the normal handoff point and a point ¹/₂ mile from the end of a runway or for secondary airports, the point where the aircraft leaves or enters the bottom fringe of the radar coverage pattern.

b. Horizontal: No tolerance assigned.

c. Vertical - Acceptance Check: A complete radar coverage pattern must be flown to determine whether the radar meets engineering and operational specifications.

d. Commissioning: The vertical coverage pattern will meet the operational requirements of the facility in both the horizontal (distance from the antenna to the outer fringe) and the vertical planes.

e. Accuracy:

f. Fix/map accuracy: Radar accuracy must be such that reporting aircraft are within a circular area about the fix, the radius of which is 3 percent of the fix-to-station distance or 500 feet (1,000 feet for air traffic control radar beacon system (ATCRBS)), whichever is the greater.

g. Fixed Target Identification: No tolerance assigned.

h. MTI: No tolerance assigned.

i. Surveillance Approaches: Radar used for surveillance approaches must present a usable target return (one which is not missed on more than two consecutive scans) through the final course as follows:

j. Approach to Runway (Straight-in): The surveillance approach course line will coincide with the runway centerline extended. Maximum error left or right of the runway edges must not exceed 500 feet at the missed approach point.

k. Approach to an Airport (Circling): The approach course may be aligned to the center of the airport or, where advantageous, to any portion of the usable landing area. For helicopters only, the final approach may be established to a missed approach point not farther than 2,600 feet from the center of the landing area, or for a point-in-space approach, to a point from which flight to the landing area must be accomplished by visual reference to a prescribed route along the surface. In each instance, approach guidance will be provided to the prescribed missed approach point. Guidance accuracy must be within 3 percent of the distance between the selected delivery point and the radar antenna.

l. Surveillance approaches must meet the tolerances in subparas c1 and c2 or will be canceled.

10-5-7. RECOMMENDED ALTITUDES FOR SURVEILLANCE APPROACHES

At locations which provide surveillance approaches, facility managers must request the office responsible for the preparation of the approach to provide the recommended altitudes for the final approach. This information will be placed in the radar facility where it will be readily available for the controllers to use as required.

10-5-8. ASDE PERFORMANCE CHECKS

One hour prior to the anticipated need to use the ASDE, turn the equipment on and evaluate its performance.