Radar Separation
Radar separation defines the minimum horizontal and vertical distance that must be maintained between two aircraft in flight.
Since safety is the top priority in aviation, controllers must ensure separation is maintained at all times. Radar separation is considered maintained when either horizontal or vertical separation (or both) exist between aircraft.
When aircraft lose both horizontal and vertical separation, it is classified as a Loss of Separation (LoS). If a controller is responsible for a LoS, it will result in an automatic failure during an exam.
Radar separation applies wherever air traffic control (ATC) has radar equipment available. In Approach and Center sectors, radar is always used to verify separation. Tower controllers at international airports also use radar screens, so radar separation must be ensured in the tower environment for departures and approaches.
A separate guide is available detailing radar separation procedures for tower controllers.
When is Separation Required?
The requirement for radar separation depends on the airspace and the applicable flight rules.
Radar Separation Requirements
Radar separation is mandatory between:
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All flights in airspace A and B (not applicable in some countries).
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IFR to IFR in airspace C, D, and E.
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IFR to VFR in airspace C.
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Special VFR to IFR within a Control Zone (CTR).
Vertical Separation
The following minimum vertical separation applies between aircraft requiring separation:
| Flight Level Range | Vertical Separation | Remarks |
|---|---|---|
| FL410 - UNL | 2000 FT | |
| FL290 - FL410 |
2000 FT | CVSM (Conventional Vertical Separation Minimum, exception) |
| 1000 FT | RVSM (Reduced Vertical Separation Minimum, standard) | |
| GND - FL245 | 1000 FT |
Vertical separation applies at both altitudes (AMSL) and flight levels (FLs).
Vertical separation is not used on final approach, where only horizontal separation is applied.
Horizontal Separation
The following minimum horizontal separation applies between aircraft requiring separation:
| Flight Level Range | Horizontal Separation |
| FL245 - UNL | 5 NM |
| GND - FL245 | 3 NM |
| Final approach (within 10 NM) | 2.5 NM |
Horizontal separation is always measured as a direct line between the centers of aircraft radar targets.
Formation Flight Considerations
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Formation flights must be separated from other traffic by 1 NM more than the required minimum distance.
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Two formation flights must be separated from each other by 2 NM more than the required minimum distance.
Wake Turbulence Considerations
If wake turbulence separation requirements exceed the above values, the higher separation value always applies to ensure safety.