AIP ENR 1.1
A pilot in command must request an airways clearance:
- on the clearance delivery frequency, preferably immediately before starting engines, otherwise as soon as possible thereafter or
- where a clearance delivery frequency is not available, before entering the departure runway and
- before entering controlled airspace.
Airways clearances normally contain the following items:
- aircraft identification
- destination, area of operation, position or clearance limit
- route of the flight
- assigned level
- SSR code and
- frequency requirements.
If an aircraft is cleared only to an intermediate point, and flight beyond that point will be in controlled airspace, a pilot in command must obtain a further clearance before proceeding beyond the intermediate clearance point.
When an aircraft leaves controlled airspace, a further clearance must be obtained for any subsequent flight in controlled airspace.
Separation in controlled airspace AIP ENR 1.4
In Class C airspace, ATC provides separation as follows:
- between IFR flights
- between IFR and VFR flights
- between IFR and special VFR flights and
- between special VFR flights when the visibility is less than VMC.
Additionally, in Class C and Class D airspace:
- appropriate runway separation is applied to all aircraft at controlled aerodromes and
- ATC provides VFR flights with traffic information on other VFR flights.
Furthermore, when requested, and as far as is practicable, ATC will provide VFR flights in Class C airspace with a suggested course of action to avoid other VFR flights.
It is the responsibility of the pilot in command to see and avoid other aircraft (CAR 163A).
Special provisions AIP ENR 1.4
The separation of aircraft taxiing on the manoeuvring area (which does not include apron and parking areas) is a joint pilot and controller responsibility. The pilot must maintain separation while complying with clearances and instructions.
In the traffic circuit, pilots must position their aircraft so that, while complying with clearances and instructions from ATC, they maintain the necessary separation from other traffic.
Separation is not normally provided within a training area in controlled airspace.
Under certain conditions, the pilot of one aircraft may be given responsibility for separation with other aircraft. In this circumstance:
- the pilot is also responsible for the provision of wake turbulence separation
- the pilot must advise ATC when they are unable to maintain, or have lost, sight of other aircraft
- where an aircraft has been instructed to maintain separation from, an IFR aircraft, ATC will issue traffic information to the pilot of the IFR aircraft, including advice that responsibility for separation has been assigned to the other aircraft
- aircraft flying in formation will not be provided with separation in respect to other aircraft of the same formation, including for take-off and landing and
- aircraft flying as part of an in-company flight will not be provided with separation in respect to other aircraft of the same in-company flight while airborne. Runway separation will continue to be provided.
In some circumstances, a number of services may operate under a common callsign and can be on a common or separate frequency:
Used by the airways clearance delivery (ACD) service when established on a discrete frequency.
Used by surface movement control and apron service (if provided by ATC) when established on a discrete frequency. At some locations this service also provides the airways clearance delivery service on the same frequency.
The following services use this identification:
• aerodrome control
• aerodrome/approach control when combined.
Used by approach control (APP) service when established on a discrete frequency or by departure control (DEP) when on the same frequency.
Used by departure control (DEP) service when established on a discrete frequency.
• Area control (ACC) service
• SIS and
Used when an aerodrome flight information service (AFIS) is being provided on a discrete frequency.
Traffic information in controlled airspace AIP GEN 3.3
In controlled airspace when a separation standard does not exist, ATC will provide traffic information to the aircraft concerned when, in the opinion of the air traffic controller, the proximity of the aircraft warrants this information.
The traffic information provided will contain as much information as is known and is necessary to assist the pilot in identifying the other aircraft. For example:
- position, either by:
- clock reference
- bearing and distance
- relation to a geographical point or
- reported position and estimate and
- intentions or direction of flight.
ATC provides relevant traffic information to aerodrome traffic to enable pilots, while complying with ATC instructions, to maintain separation from other aircraft.
At military aerodromes traffic conditions may preclude the transmission of a complete traffic information service to individual aircraft.