Radar Services and Radar Vectoring

Radar (today more generally: ATS surveillance) lets a controller see where aircraft actually are, instead of relying on position reports. This enables a family of services — vectoring, radar separation, monitoring, surveillance approaches and traffic information — described in ICAO Annex 11 and ICAO Doc 4444 PANS-ATM, Chapter 8. As a VFR PPL pilot you will most often encounter radar services when receiving traffic information from FIS or when transiting controlled airspace, but the exam expects you to know the full set of services and the pilot's duties when being vectored.

The five surveillance-based services

1. Radar vectoring. The controller issues headings to the pilot to guide the aircraft along a specific path — while being vectored, the pilot flies headings instead of navigating himself. Phraseology: "Turn left/right heading 240", "Maintain heading 270". Vectoring is used for approach guidance onto the localizer/final, for separation from other traffic, for weather avoidance and for keeping aircraft clear of restricted areas.

2. Radar separation. The controller establishes and monitors minimum distances between aircraft by radar, instead of using procedural separation. Standard horizontal minimum: 5 NM (reduced to 3 NM in TMA/CTR with suitable radar coverage); vertical: 1000 ft.

3. Radar monitoring. The controller watches the aircraft's track on the radar display and warns of deviations from the cleared route or level.

4. Surveillance approaches. Approach guidance by radar: SRA (Surveillance Radar Approach — azimuth and advisory altitudes) or PAR (Precision Approach Radar — azimuth and glide path).

5. Traffic information. Even for flights that are not radar-separated (e.g. VFR in airspace E or with FIS), the controller can pass traffic information: "Traffic 12 o'clock, 5 miles, opposite direction, 2000 ft".

Pilot obligations during vectoring

Follow assigned headings as accurately as possible.
Maintain the assigned altitude — a vector is not a clearance to change level.
Inform ATC if an instruction cannot be complied with (bank-angle limits, weather, emergency).
On "Vectoring terminated, resume own navigation", the pilot takes back responsibility for navigation.

Terrain clearance and the MVA

The MVA (Minimum Vectoring Altitude) is the lowest altitude at which a controller may vector an IFR flight in a given sector, guaranteeing obstacle clearance. ATC shall not vector an IFR flight below the MVA; terrain clearance during vectoring is the controller's responsibility. Once the pilot resumes own navigation, responsibility for terrain clearance returns to the pilot.

Radar identification

Before any surveillance service can be provided, the controller must identify the aircraft on the display (Doc 4444, Chapter 8). Typical methods:

Instructing "Squawk ident" and observing the ident flash,
Assigning a discrete transponder code and observing it appear,
Instructing a turn of 30° or more and observing it,
Correlating a position report from the pilot with an observed radar target.

Europe (EASA / EU)

Regulation (EU) 2017/373, Annex IV (Part-ATS) requires surveillance-based services at commercial airports and in TMA/CTR; the associated procedures follow ICAO Doc 4444.

Germany (national)

DFS provides radar services at all commercial airports (FRA, MUC, DUS, …), in the TMAs and in the area control centres. MVAs and radar procedures are published in the AIP Germany. In uncontrolled airspace (G) there is no radar vectoring: FIS ("Langen Information" etc.) provides traffic information and other flight information only — the pilot remains fully responsible for navigation and terrain clearance.

Exam essentials

Surveillance-based ATS comprise radar vectoring, radar separation, radar monitoring, surveillance approaches (SRA/PAR) and traffic information.
During vectoring the pilot flies assigned headings; navigation responsibility rests with the controller until "resume own navigation".
Standard radar separation is 5 NM horizontally (3 NM in TMA/CTR with suitable radar) or 1000 ft vertically.
ATC shall not vector an IFR flight below the MVA; terrain clearance during vectoring is the controller's responsibility.
The pilot must inform ATC if a vectoring instruction cannot be complied with.
Radar identification methods include squawk ident, a discrete code assignment, an observed turn of 30° or more, and correlation of a position report.
FIS in airspace G provides traffic information only — no radar vectoring.