Operations resources


Class E and Class G airspace

Home > Operations > Class E and Class G airspace > Surveillance Information Service in Class E and Class G airspace Print this page

Surveillance Information Service in Class E and Class G airspace



Summary of surveillance information service (SIS)

SIS services available include:

  • alerting service for all flights receiving SIS
  • flight following upon request
  • priority assistance when pilot prefixes requests with ‘Mayday’ (three times)  or ‘Pan Pan’ (three times).


SIS is available, on request, to VFR flights in Class E and G airspace within ATS surveillance system coverage, subject to ATC workload. The SIS is available to improve situational awareness and assist pilots in avoiding collisions with other aircraft.

Pilots wanting to receive an SIS must be in direct VHF communications with ATC and equipped with a serviceable SSR transponder or ADS-B transmitter.

VFR pilots receiving an SIS will be provided with traffic information and, upon request, position or navigation information.

Pilots of VFR flights receiving an SIS will be provided with information about ATS surveillance system-observed traffic. However, due to the nature and type of ATS surveillance system coverage, not all aircraft will be detected, and not all aircraft are equipped with an SSR transponder or ADS-B transmitter. Consequently, traffic information provided by ATC may be incomplete. Pilots must comply with the see-and-avoid requirements of CAR 163A.

ATC will provide an alerting service for flights receiving an SIS.

On initial contact with ATC, the pilot must advise the ATS surveillance service required and, if an ongoing service is requested, include the phrase ‘Request flight following’.

When ATC responds to this request, the pilot must advise position, level and intentions.

The SIS commences on ATC notification of identification, and ATC may also assign  a specific transponder code prior to, or during, the provision of the SIS.

If ATC is unable to provide an SIS, the pilot will be advised ‘Surveillance service not available’. Requests for emergency assistance should be prefixed by ‘Mayday’ (three times) or ‘Pan Pan’ (three times), and will receive priority.

If, following a request for an SIS, a request for flight following is not made and the requested information has been provided to the pilot, ATC will advise ‘Identification terminated’ to indicate that the surveillance service is terminated.

If the pilot has requested flight following, the SIS will be provided on an ongoing basis, generally limited to within the controller’s area of responsibility. However, the SIS may be terminated at any time by the controller, or by pilot advice
While receiving an SIS, the pilot must:

  • maintain a continuous listening watch with ATC and advise prior to leaving the frequency and
  • advise ATC prior to any changes to track or level.

Approaching the boundary of the controller’s area of responsibility, the pilot will generally be advised ‘identification terminated, frequency change approved’.  If a continued service is requested, the pilot must advise ‘request hand-off for  flight following’ and, subject to the approval of the adjacent ATC unit, the pilot  will be instructed to change frequency for continuation of the SIS.

Alerting service AIP GEN 3.3

An alerting service will be provided:

  • for all aircraft provided with ATC service
  • in so far as practicable, to all other aircraft that have filed a flight plan or are otherwise known to the air traffic services
  • to any aircraft known or believed to be the subject of unlawful interference

Back to top
New rules came into effect from 2 December 2021 that cover the general operating and flight rules. This website is now out of date and will be switched off in the new year. A PDF copy of the VFRG is available for download.
This is default text for notification bar