European Free Flight basically views suitably equipped "autonomous aircraft" able to efficiently fly user-preferred 3D or 4D routes in selected airspace, and to separate themselves from other aircraft according to suitable level of traffic density. In this perspective, responsibility for separation assurance from other aircraft remains within the aircraft in almost all circumstances, although ground-based ATM (e.g. emergencies) can still undertake some responsibility. The freedom for aircrew to select the preferred trajectory and to perform self-separation is expected to allow the possibility for better operating in response to user objectives.
The geographic location of the Mediterranean area between the European core area and the states of north Africa and the Near East is a critical factor regarding future air navigation service provision in Mediterranean coastal states.
This boundary situation along with the Mediterranean peculiarity of low air traffic complexity scenario is an attractive draw to address studies and validation trials concerning the latest CNS technologies and most recent operational concepts identified in the ECAC "ATM 2000+ Strategy" to accomplish EATMS.
Mediterranean Free Flight was a pre-operational programme aimed at defining, testing and validating free flight applications and procedures within selected Mediterranean scenarios in free-flight airspace and between free-fligth and managed airspace.
Airborne separation assurance is a fundamental concept introduced by Free Flight, and the Airborne Separation Assurance System (ASAS) is the main enabler. The ASAS concept covers several applications. The following were investigated in the MFF programme:
Traffic situational awareness.
Co-operative ASAS (including airborne spacing assurance and airborne separation assurance) in managed airspace.
Airborne self-separation assurance in free-flight airspace.
The main objectives of the MFF programme were to:
- provide technical and operational evaluation of integration, interoperability and safe use of CNS/ATM technologies and applications suitable for future Mediterranean ATM scenario (e.g. operational requirements and procedures based on the use of new CNS/ATM technologies enabling the introduction of free flight operations in Mediterranean area).verify appropriate new operative procedures for ATM staff and crew in free routing and free flight scenarios (e.g. the delegation of separation responsibility from ATC to aircraft and vice versa, through simulations and flight trials using specially equipped aircraft and controller working positions).
- take advantage of the inherent results to address standardisation and further maturation of relevant CNS/ATM technologies and applications both in ground systems and avionics.
- define guidelines to implement free flight operations in suitable parts of the airspace.
On the basis of the user expectations and traffic constraints, the MFF programme defined operational requirements and procedures for the future implementation of free flight in the Mediterranean area. Requirements and procedures were matched with available CNS technologies to obtain the specifications for an integrated ground-airborne test bed system able to assess the feasibility of free flight in the Mediterranean area.
Based on this specification, a test bed was implemented. A real-time simulation was carried out and flight trials were executed. It is to be noted that en-route airspace with low-density level of air traffic characterises the MFF flight trials.
The programme also covered validation, operational benefits and safety case aspects and activities.
MFF, a five years Programme made possible by the co-funding of the European Commission, represents one of the largest multinational initiatives in the history of European Programmes to enhance the future ATM System. Experts from nine countries with diff erent cultural backgrounds contributed to the successful achievement of the MFF goals. Considering the wide scope, the range of development work and validation efforts undertaken by MFF, the whole Programme provided valuable scientific results which can, with further studies based on “lessons learned”, facilitate the highly needed improvements of the European ATM system and concept of operations.
Four innovative operational applications were investigated in detail by MFF:
- Free Route;
- ASAS Spacing;
- ASAS Separation;
- ASAS Self-Separation (Free Flight).
Air Traffi c Situational Awareness (ATSAW), originally in the MFF applications list, has been considered as an enabler for the above applications and therefore implicitly evaluated.
MFF has carved new ground in the validation of the studied operational Concepts, allowing the collection of extensive experimental results. However, in order to cover the next steps towards implementation, it appears necessary to involve a larger group of stakeholders (including Airlines, Aircraft manufacturers, Avionic Industries, Airports and so forth).
On explicit indication of the European Commission, SESAR shall be the framework in which the MFF results could be further explored and successively exploited ensuring at the same time the participation of an adequate group of stakeholders.