9 ATC SEPARATION

9.1 Separation Provided
- 9.1.1 Separation is provided by ATC:
  - (b) between IFR and VFR flights in class C airspace;
  - (c) between IFR and SVFR flights;
  - (d) between SVFR flights when the flight visibility is reported to be less than 5 km; and
  - (e) at controlled aerodromes when defined runway and wake turbulence separations are applicable. Wake turbulence separations applicable to all phases of flight are listed in AD 1.6.
9.2 Separation Not Provided
- 9.2.1 Separation is not provided:
  - (a) between IFR flights in Class G airspace;
  - (b) between IFR and VFR flights in Class G airspace; between IFR and VFR flights in Class D airspace; between an IFR flight at the lowest usable cruising level in Class C airspace and a VFR flight in Class D airspace operating at the common airspace level;
  - (c) between SVFR flights when the flight visibility is reported to be 5km or greater;
  - (d) between VFR flights, except at controlled aerodromes when defined runway and wake turbulence separations are applicable. (Within the circuit at controlled aerodromes, an aerodrome control service is provided in which instructions, clearances and information are issued to VFR flights to prevent collisions and to achieve defined runway and wake turbulence separation.)
  - (e) between a flight known to be responding to a TCAS RA, or a GPWS or TAWS alert, and other flights where separation is normally provided as listed above. When the pilot advises "Clear of conflict", ATC will make every endeavour to restore standard separation and an orderly flow of traffic. ATC responsibility for maintaining separation resumes from the time that separation is re-established between all aircraft involved in the manoeuvre.
9.3 Essential Traffic
- 9.3.1 Essential traffic is that controlled traffic to which the provision of separation is applicable, but which, in relation to a particular controlled flight, is not separated by the prescribed minima. Essential traffic includes flights which are maintaining own separation in VMC, and flights affected as a result of an aircraft responding to a TCAS RA.
- 9.3.2 Essential traffic information, of the aircraft concerned, will include:
  - (a) the words "ESSENTIAL TRAFFIC";
  - (b) direction of flight;
  - (c) type of aircraft;
  - (d) altitude; and
  - (e) position information.
- 9.3.3 Following the passing of essential traffic, or traffic information in Classes C and D airspace, pilots may request traffic avoidance advice. The provision of traffic avoidance advice is intended to assist pilots but does not absolve them of the responsibility to avoid collision with other aircraft.
- 9.3.4 The separation standards detailed in the following paragraphs are the minimum and may be increased, at the request of the pilot or by ATC, if considered necessary in the interests of safety.

9.4 Vertical Separation

9.4.1 Vertical separation between controlled flights is 1000 ft below FL290, or 2000 ft above FL290, except that this may be reduced to 1000 ft in RVSM airspace if both aircraft are RVSM approved. The 1000 ft standard may be reduced to 500 ft within controlled airspace providing both aircraft are medium or light weight category aircraft, and the lower aircraft is VFR or SVFR operating at an altitude of 4500 ft or below.
9.4.2 Where vertical separation from Special Use Airspace is required, controlled flights will be required to fly at levels which ensure the separation minima specified in Table ENR 1.1-1, above or below the airspace. Where no minimum is specified aircraft will be kept clear of the airspace.

Table ENR 1.1-1
Designated Airspace	Upper/Lower limit of airspace
Designated Airspace	Below FL290	At or above FL290
Danger, Restricted or Military Operating Areas established for aircraft activity in IMC or Special VFR	1000 ft	2000 ft
Danger, Restricted or Military Operating Areas established for aircraft activity in VMC	500 ft	1000 ft
Danger, Restricted or Military Operating Areas NOT established for aircraft activity	no minimum	no minimum
Volcanic Hazard Zones	no minimum	no minimum

9.4.3 When climbing or descending in Classes A, C, and D airspace unless ATC has specified a climb/descent rate and/or time or place of commencement, pilots must initiate climb or descent promptly on acknowledgement of the clearance, or advise ATC so that separation from other traffic will not be compromised. The change of level should be made at an optimum rate consistent with the normal operating performance and configuration characteristics of the aircraft to 1000 ft above/below the assigned level, then reduced as appropriate until the assigned level is reached. At other times in climb or descent, pilots must advise ATC if they wish to level off at an interim level or substantially change the rate of climb or descent.
9.4.4 When a rate of climb or descent is specified by ATC, pilots must comply, or immediately advise ATC if they are unable to comply. When a rate of climb is specified from departure, pilots should ensure that the required rate of climb:
- (a) can be sustained; and
- (b) will ensure appropriate terrain clearance.

9.5 Horizontal Separation
- 9.5.1 Horizontal separation may consist of:
  - (a) longitudinal separation;
  - (b) lateral separation;
  - (c) radar separation;
  - (d) geographical separation.
- 9.5.2 Longitudinal separation of aircraft is applied so that the spacing between the estimated positions of the aircraft concerned is never less than the prescribed minimum. This minimum will be expressed as a distance or time.
- 9.5.3 Longitudinal separation is achieved by requiring aircraft:
  - (a) to depart at a specified time;
  - (b) to lose time to arrive over a specified location at a specified time;
  - (c) to hold at a specified location until a specified time; or
  - (d) by insuring that aircraft are never less than a specified distance apart.
- 9.5.4 Aircraft on reciprocal tracks outside of radar cover may be requested to report sighting and passing other aircraft, by day or night, in order to permit a reduction in longitudinal separation. It is the pilot's responsibility to ensure correct identification of other aircraft. If pilots are unwilling to accept the application of this separation standard, they should not acknowledge the sighting and passing of other traffic.
- 9.5.5 Aircraft are considered to be laterally separated provided their positions along track are outside an area known as the area of conflict. The area of conflict is established by applying the navigation tolerance for the navigation aid being used for track guidance, plus a buffer area, to the two tracks. The point at which the buffer areas cease to overlap is termed the lateral separation point and is normally expressed as a distance from a navigation aid or reference point.
- 9.5.6 If a distance reference is not available, entry to, or exit from an area of conflict may be determined by radar, or by the passage of an aircraft over:
  - (a) a point beyond the lateral separation point determined by a radio navigation aid; or
  - (b) a point beyond the lateral separation point determined by visual reference. (Available during hours of daylight only.)
- 9.5.7 When two aircraft will enter an area of conflict, action will be taken by ATC in sufficient time to ensure that vertical or longitudinal separation exists before the second aircraft passes the lateral separation point on its route. Should doubt exist that an aircraft can reach its assigned altitude before lateral separation is lost, the pilot must confirm the ability to meet the terms of their clearance.
- 9.5.8 Radar separation is detailed in ENR 1.6 paragraph 5.13. Wake turbulence separation is detailed in AD 1.6 paragraph 1.3.
- 9.5.9 Geographical separation is achieved by requiring one or more aircraft, which are operating by visual reference, to follow tracks identified by prominent geographical features, landmarks or visual reporting points, or to remain within specified CTR/CTA sectors, which have been determined as being geographically separated from other tracks or procedures. Geographical separation may be applied within terminal control areas and CTR up to 6000 ft AMSL.
- 9.5.10 Navigating by visual reference in order to achieve geographical separation requires aircraft to use Visual Navigation Charts or an electronic equivalent. For flights when either a visual departure or visual approach might be anticipated appropriate visual navigation charts or an electronic equivalent should be carried.
- 9.5.11 ATC use of DME or GNSS to establish or maintain horizontal separation is normally subject to direct speech between aircraft and the ATC unit concerned.
9.6 Visual Separation (Reduced Separation)
- 9.6.1 In Classes C and D airspace, vertical or horizontal separation may be reduced by the application of visual separation provided that:
  - (a) such clearances will only be issued during hours of daylight; and
  - (b) a specific request is made by a pilot; and
  - (c) the pilots are in direct communication with the ATC unit on the same frequency, except when under the control of adjacent radar positions sharing common airspace; and
  - (d) both flights remain in VMC; and
  - (e) there is no possibility of incorrect identification; and
  - (f) each aircraft is continuously visible to the pilot of the other aircraft; and
  - (g) both pilots concur with the application of the procedure; or
  - (h) the pilot of the succeeding aircraft reports having the preceding aircraft in sight and can maintain visual separation.
- 9.6.2 Vertical or horizontal separation may be reduced in the vicinity of aerodromes if:
  - (a) adequate separation can be provided by the aerodrome controller when each aircraft is continuously visible to that controller; or
  - (b) each aircraft is continuously visible to the pilot of the other aircraft concerned and both pilots report that they can maintain visual separation; or
  - (c) in the case of one aircraft following another, the pilot of the succeeding aircraft reports the preceding aircraft in sight and can maintain visual separation.
- 9.6.3 Composite visual separation is the application of visual separation by an aerodrome controller in circumstances where only one aircraft is visible to the controller, but both the position and the track of a conflicting aircraft are known and the application of geographical separation is not practicable.
- 9.6.4 Aerodrome control may use composite visual separation to separate an aircraft which is continuously in sight of the aerodrome controller and within 10 NM of the aerodrome, from an aircraft not in sight of the aerodrome controller provided that:
  - (a) the route and intentions of the aircraft which is not in sight are known and its position can be confirmed by radar or other means; and
  - (b) instructions when required, are issued to the aircraft in sight which will ensure adequate separation.