Provision of Services by Third Party Service Providers

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Provision of Services by Third Party Service Providers

34TH ANNUAL CONFERENCE, Jerusalem, Israel, 27-31 March 1995

WP No. 103

Provision of Services by Third Party Service Providers


The objectives of the ICAO CNS/ATM concept is to bring into service a global ATM system. The enabling technologies that allow this objective to be realised use advances in satellite and telecommunications systems. The cost of providing an infrastructure to meet the needs of the ATM users is considerable, and will be beyond the means of some if not many states.

There are a number of organisations that provide telecommunications services for the aeronautical community today, who can provide components of the infrastructure required to enable the global ATM system to function. These are commercial organisations such as ARINC, SITA and INMARSAT. In some cases these organisations already provide such services, such as ARINC for the FAA with communications over Oceanic airspace. These organisations, or third party service providers, therefore will play an important role in the efficiency and safety of the ATM service.

Issues relating to the use of third party service providers

It is important to note that this is one of the major differences in the way that ATS is to be provided in the future. Today, in most cases, the ATS service provider is responsible for the communications links. That is the CAA’s plan, procure and maintain the communications networks, transmitters and receivers. In an ADS-ATC mode of operation, this is not necessarily the case. ATS providers will not be able to afford SATCOM for example. Thus these services will be provided by third party service providers, such as INMARSAT in the case of SATCOM, and SITA and ARINC in the case of VHF datalink for example. ARINC already provide HF communications for the FAA over oceanic areas, so it is not an entirely new idea.

The cost of providing the service will therefore be a major issue, for a charging structure must be set, and capacity be provided along with performance targets to ensure no interruptions of service. However, the cost of using networks provided by third party service providers, when compared with networks in CAA ownership, may be more expensive. Aircraft operators will rightly seek to minimise the costs of ADS operation. Presently, an ADS normal reporting rate will be one in every 300 seconds. This may be acceptable for normal monitoring surveillance. When a controller uses ADS to perform tactical control of aircraft, there will be a requirement for a greater reporting rate – en-route radar refresh rates are typically of the order of 1 every 6 to 10 seconds. Thus the actual cost of providing tactical control for a period of time using ADS will be greater than for a comparable period of time where only the normal ADS reporting rate is used.

The implications of this characteristic of ADS operation means that the cost of service provision potentially conflicts directly with the user. Tactical control of aircraft, as are all ATC tasks, are flight safety critical. If a safe and efficient ATC service is to be provided there can be no acceptable compromises that will degrade the quality, quantity, and timeliness of information provided to the controller. Limiting the ADS reporting rate provided to ATC to meet economic targets therefore is unacceptable.

The networks that the third party service providers use, will also be available to other stakeholders of the aeronautical community. ATC is a safety critical function, and the consequences of delay in the transmission of messages for ATC purposes can have catastrophic consequences. Additionally, as these networks are accessible by users other than ATC, there is a risk, no matter how small, that the security of information can be compromised.

Therefore the networks and services that third party service providers use should be evaluated and certificated as being suitable for the level of safety for the function that they support. Networks must operate using a message prioritisation system should that ensures that ATC messages receive the highest unassailable priority. System failures and backup modes of operation must be available to enable continuation of safe operations and to limit system downtime. Assurances must be made to the ATC authorities on the security of the networks from interference.

To Conclude

The use of third party service providers to make available the global communications links that ADS operations will require is a practical way of overcoming the limited resources that CAAs have available. The services that third party service providers will therefore enable an early implementation of ADS into operation.

CAA’s will not have ownership of the communications links that third party service providers offer. There are particular areas of concern that can directly impinge upon the safety and efficiency of air traffic services.

It is recommended that:

Where aeronautical telecommunications services are provided by third party service providers, ATC message traffic must have the highest unassailable priority.

Aeronautical telecommunications facilities provided by third party service providers and used in ADS operations must meet the appropriate standards for the operation of a safety critical service.

ADS reporting rates should be determined by the ATS operational requirement.

Procedures for the provision of an ADS-ATC service shall not impose any restriction upon the controller on requesting reports from aircraft under ADS control.

In providing a service for the aeronautical community, the third party service provider must provide assurances on the integrity of information and security from interference.

Last Update: September 28, 2020  

February 12, 2020   672   Jean-Francois Lepage    1995    

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