Automatic Dependent Surveillance - Broadcast (ADS-B) systems have created a revolutionary change to Air Traffic Management (ATM) and the implementation of this technology is securing safety and increasingly efficient utilisation of airspace internationally.

There are now many providers of easily available ADS-B software and applications that captivatingly display aircraft positions and performance data on smart devices and laptops for educational and casual use.  These third-party systems gather aircraft data (location, altitude, ground speed etc) from further third parties for proprietary processing and presentation.

The appearance and apparent performance of these systems is such that Air Navigation Service Providers (ANSP) may see this as an opportunity to implement an air traffic surveillance system to exploit benefits cheaply and easily.  Such an assumption is seriously flawed as these freely available systems can create safety risks regardless of the type of air traffic surveillance provided (ie separation and situational awareness).  It is therefore mandatory that any ADS-B system used by UK Overseas Territory ANSPs is approved under the Air Navigation (Overseas Territory) Order.

ADS-B based surveillance systems that have been approved by Civil Aviation Authorities are subjected to technical and operational analysis to ensure compliance with ICAO, regional and national performance requirements.  Such detailed analysis is not possible for generic third-party ADS-B system providers who typically repudiate use for safety related purposes and do not guarantee nor take any responsibility for the correctness, validity and accuracy of information.  Should an ANSP seek to use a generic third-party ADS-B system, regardless of purpose, it falls upon the ANSP to identify risks caused by non-compliance with applicable standards and to claim acceptable means of compliance to the Regulator. 

The following elucidates the shortcomings associated with the use of generic third-party ADS-B display systems:

• Inability to configure the system for the specific purpose:

• Data uncertainty and integrity criteria will not be optimised for the intended area of use and can cause aircraft position to display in an incorrect position or not at all;
• Data timeliness criteria may not be applicable to the specific purpose (eg turn 'rich' approach and departure regions) causing aircraft position to display in an incorrect position or not at all;
• Third party ADS-B system providers accept requests for specific aircraft to be removed from display;
• There is no means to implement and guarantee timely alerts of service degradations that may impact on the safety integrity of a specific service being provided.

• The absence of jurisdiction over the airspace where surveillance is intended (eg beyond Aerodrome Traffic Zone):

• Cannot mandate ADS-B (ADS-Broadcast) carriage and hence aircraft may not be displayed;
• ADS-B equipment aircraft carriage may not be compliant and data provided may be erroneous and cause an aircraft to be displayed in a wrong position or not at all.

• Third party ADS-B systems are not designed with a user interface applicable for an air traffic safety related environment:

• Users can change user parameters (eg range, filters) that can cause aircraft to be hidden from display and generally renders the system vulnerable to human factors;
• Could lead to the presence of multipurpose devices in an operational environment that could cause dangerous distraction, eg smart phones, tablets, laptops.

It is emphasised that even if ADS-B information is used for situational awareness purposes, the presentation of aircraft in incorrect positions or not at all can lead to tactical decisions that can unintentionally bring aircraft into unsafe proximity.