17.7 Radar Separation. There is only one radar separation standard and this is 5 NM. As defined in Chapter 16, reduced radar separation may be applied under specific conditions. The separation applied is based upon the aircraft position derived from PSR only. As defined and specified in Chapter 16, wake turbulence separation can be applied using radar derived information. In this case the separation standards applied are based on distance.

Radar Identification

17.8 Requirement. Before a radar controller can provide any service to an aircraft, the radar identity of the aircraft must be established. Clearly, the basic SSR capability is to identify a specific aircraft squawking a specifically allocated code, therefore this method of identification is most commonly used. It is also the quickest method of identification. Once an aircraft has been allocated an SSR code, it must be retained until otherwise advised by the radar controller. If an emergency situation arises, the pilot should not squawk A7700 if the identity of the aircraft has already been established using SSR. All other methods of identification by radar require the ATCO to observe the radar contacts on the display screen and determine, either from geographic position or from a specific manoeuvre, which contact is the aircraft requiring the service. Such observations include:

•Geographic location e.g. ‘2 NM west of Woodstock’

•Relative to a radio navigation aid - “On the 230 radial from the Daventry VOR DME 5 NM”

•Latitude and longitude

•Georef position

•Turn through 30° or more away from desired course and then return to the course

•Positive handover from a radar controller who had previously identified the aircraft

17.9 Procedure. When identifying a radar contact as a specific aircraft, the radar controller must tell the pilot how the identification was achieved. The controller will use the phrase ‘radar contact’ to indicate that the aircraft has been identified and that until further advised, a service will be provided - “G-CD radar contact 2 NM west of Oxford”. This position should agree with the position the pilot thinks the aircraft is at. If significantly different, the pilot must inform the controller in the event that the controller has misidentified the aircraft.

Radar Service

17.10Commencement. After identification, the pilot is to be told what type of radar service is to be provided and what the objective is - “G-CD radar contact 6 NM west of Compton, radar control, expect radar vectors for ILS approach runway 26”

17.11Termination. When an aircraft reaches the limit of radar cover or the edge of a radar vectoring area, or the aim of the service has been achieved, the pilot will be advised that the service is terminated, given position information and instructions/advice how to continue. For instance: “G-CD radar service terminated, presently 10 NM south of Benson, resume own navigation, suggest continue with London Information 125.650”

Control of Aircraft 17

Aircraft of Control 17

17.12 Radar Vectoring. Radar vectoring is the passing of navigation information to a pilot by a radar controller to achieve the aircraft flying a required track. This may be simply to avoid weather or manoeuvre around another aircraft radar contact. Once the aim of the vectoring has been achieved, the pilot will be told to “Resume own navigation” giving the pilot the aircraft’s position and any appropriate instructions. This implies that the radar vectoring has ended. It may be provided to position the aircraft such that a straight-in instrument approach can be achieved. In any event, radar vectoring for approach control purposes is only carried out inside a radar vectoring area (RVA). Obstacles are marked on an RVA chart.

MSA outside of RVA

Radar Vectoring

Area Boundary

Safety altitude inside of RVA

Figure 17.3 Radar vectoring area

17.13 Vectoring Procedure. Radar vectoring will not begin until the aircraft radar contact is determined to be within the RVA. The RVA will be displayed on the radar display in the form of a video map electronically generated within the radar display software. Because of possible inaccuracies (‘slippage’) aircraft will not be radar vectored closer to the edge of the RVA than half the applicable radar separation standard or 2.5 NM whichever is greater. Normally, radar vectoring will begin at a fix at MSA. It may, however, begin at any time after the aircraft has been identified on radar and the aircraft altitude is known to the ATCO. The RVA chart displays the obstacles in the area together with the elevation of the terrain. The radar controller will pass magnetic headings to the pilot to steer to make good a desired track over the ground. The pilot will fly the heading and the controller will adjust the heading for the wind. The aircraft will not be given clearance to descend below the RVA safe altitude (highest obstacle in RVA plus MOC rounded up) until established on the ILS localizer course or on the final approach track, or the pilot reports that he/she is continuing the approach visually. Throughout the procedure, the radar controller must be aware of the elevation of the terrain and the aircraft configuration to avoid spurious GPWS warnings.

Aircraft of Control 17

LHA 2000

Initial and Intermediate Approach as directed by radar.

NOTE MAXIMUM IAS for Missed Approach Procedure 250KT.

Figure 17.5 SRA approach

17.17 SRA. An SRA approach is a non-precision procedure using TAR and will therefore have a determined MDA/H. The procedure for SRA is similar to PAR except that in this case advisory height information is passed with range information e.g. “5 miles from touchdown, you should be passing one thousand five hundred and fifty feet”. SRA approaches always have an RTR