C1 - ATS Principles

Question 1

ICAO defines FIS as…

Answer 1

…a service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights

Question 2

Regardless of the ATS being provided…

Answer 2

…pilots are ultimately responsible for collision avoidance and terrain clearance

Question 3

ATS provision is constrained by…

Answer 3

…the nature of the airspace environment in which the flight takes place

Question 4

It is not mandatory for a pilot to be in receipt of…

Answer 4

…an ATS in Class E/G airspace and this generates an unknown traffic environment in which controller/FISO workload cannot be predicted and where pilots may make sudden manoeuvres, even when in receipt of an ATS.

Question 5

Nothing in this CAP prevents controllers from…

Answer 5

…using their own discretion, initiative and professional judgement in response to unusual circumstances, which may not be covered by the procedures herein.

In dealing with any such situations, controllers shall take account of the duty of care requirements at Appendix A

The nature of the ATS task in providing the UK FIS means that it is not possible to be totally prescriptive about all actions to be taken, particularly with regard to unknown traffic and the passing of advice and warnings on high risk conflictions to pilots who have requested Basic Service and Traffic Service.

Consequently, there is a need for controllers/ FISOs to remain free to use their professional judgement to determine the best course of action for them to take for any specific situation.

Question 6

Deconfliction Service and Procedural Service are only available to flights in…

Answer 6

…Class G airspace operating under IFR

Question 7

Basic Service and Traffic Service are available to flights in…

Answer 7

…Class G airspace operating under both IFR and VFR and in Class E airspace operating under VFR

Question 8

Controllers shall make all reasonable endeavours to provide the…

Answer 8

…ATS that a pilot requests.

However, due to finite ATS provider resources or controller workload, tactical priorities may influence ATS availability or its continued provision.

Therefore, a reduction in traffic information and/or deconfliction advice may have to be applied, and in some circumstances an alternative ATS may have to be provided in order to balance overall ATS requirements.

Question 9

Instructions issued by controllers/FISOs to pilots operating outside controlled airspace…

Answer 9

…are not mandatory; however, the ATS rely upon pilot compliance with the specified terms and conditions so as to promote a safer operating environment for all airspace users

Question 10

Agreements can be established between a controller and a pilot on a short-term tactical basis, such that the operation of an aircraft is…

Answer 10

…laterally or vertically restricted beyond the core terms of the Basic Service or Traffic Service.

This is for the purposes of co-ordination and to facilitate the safe use of airspace, particularly those airspace users with more stringent deconfliction requirements.

In agreeing to a course of action, pilots must take into account their responsibilities as defined under the Rules of the Air, including that for terrain clearance

Question 11

Unless safety is likely to be compromised, a pilot shall not…

Answer 11

…deviate from an agreement without first advising and obtaining a response from the controller.

Controllers shall remove restrictions as soon as it is safe to do so.

Question 12

Agreements may be made which restrict aircraft to a specific…

Answer 12

…level, level band, heading, route, or operating area.

Question 13

Controllers should be aware that not all requests for an agreement will be accepted and they should try to take account of…

Answer 13

…the pilot’s operating requirements whenever possible.

Consequently, controllers should avoid excessive or unnecessary use of agreements and be prepared to act accordingly if an agreement is not met

Question 14

A pilot shall determine the appropriate ATS for the various phases and conditions of flight and request that ATS from the controller/FISO.

If a pilot fails to request an ATS, the controller/FISO should normally ask the pilot to specify the ATS required, apart from the following circumstances:

Answer 14

• FISOs will only provide a Basic Service;
• Controllers at approved ATC Units that do not have surveillance equipment available will routinely apply a Procedural Service to aircraft carrying out IFR holding, approach and/or departure procedures;
• Where ATC are unable to provide the full range of UK FIS to aircraft about to leave controlled airspace, a controller should specify the ATS that are available.

Question 15

There may be circumstances that prevent controllers from passing timely traffic information and/or deconfliction advice, e.g…

Answer 15

…high workload, areas of high traffic density, unknown aircraft conducting high energy manoeuvres, or when traffic is not displayed to the controller or is obscured by surveillance clutter.

Controllers shall inform the pilot of reductions in traffic information along with the reason and the probable duration; however, it may not always be possible to provide these warnings in a timely fashion

Question 16

Describe issues which could prevent the (timely) detection of conflicting traffic

Answer 16

In high workload situations, which may not always be apparent from RTF loading, controllers/FISOs may not always be able to provide timely traffic information and/or deconfliction advice. High workload situations may not necessarily be linked to high traffic density.

High traffic density can cause difficulty interpreting ATS surveillance system data and may affect RTF loading or controller/FISO workload to the extent that the controller/FISO is unable to pass timely traffic information and/or deconfliction advice on all traffic.

Where aircraft are operating close to the lateral and/or vertical limits of solid ATS surveillance system cover, or close to a radar overhead, there is the potential for conflicting traffic to be detected late. Similarly, there is potential for aircraft to be undetected or detected late in known areas of poor surveillance performance, permanent echoes, weather clutter or when the controller suspects the performance of the ATS surveillance system is degraded.

Surveillance clutter may be generated by: weather, anomalous propagation, ground/sea returns, birds, wind turbine effects, and radar countermeasures such as chaff. In areas of clutter, the ability to detect conflicting aircraft is reduced.

Where primary radar is unavailable, and SSR alone is used to provide an ATS, non- transponding aircraft will not be detected; therefore ATC will not be able to warn pilots of their proximity.

Question 17

An Alerting Service shall be provided in association with…

Answer 17

…all UK FIS