Flight planning, the air route network and airspace design in Europe

Who decides where aircraft can fly? What happens if the airspace is unsafe to fly in? How is the European air route network built and managed? This special dossier provides you with a quick overview of how the system works in Europe.

Flight plans

All flights into, around and out of Europe that need air traffic services must be the subject of a flight plan submitted to the EUROCONTROL Network Manager’s Operations Centre (NMOC). The NMOC provides a centralised flight planning processing and distribution service through the Integrated Initial Flight Plan Processing System (IFPS). This system covers part of the ICAO EUR Region, also known as the IFPZ (IFPS zone).

For those flights which may be subject to ATFM, flight plans must be submitted at least 3 hours before the estimated off-block time (EOBT) and up to a maximum of 120 hours, or five days, in advance. The IFPS also processes those messages which, for operational reasons, are filed less than three hours before the EOBT of the flight in question. Flight plans sent to the IFPS less than 3 hours before the EOBT are deemed to be “late filers", which may be penalised during the slot allocation process.

Repetitive flight plans are submitted to the NMOC in advance for winter and summer periods. Any changes to the EOBT of more than 15 minutes for any instrument flight rule (IFR) flight within the IFPZ must be communicated to the NMOC.

A sovereign matter

States with potentially hazardous airspace (where there is very bad weather, for instance, or conflict zones) decide when to close that airspace. Sovereign States alone have this authority; no international body can do this on their behalf.

State registries of aircraft can prohibit their registered aircraft to fly in zones that they consider dangerous.

Airlines can decide which routes they allow their airliners to fly. They are guided by NOTAMs (Notices to Airmen) informing them about any airspace that States have closed; Safety Bulletins issued by the European Aviation Safety Agency or State Letters written by the UN’s International Civil Aviation Organization.

The ultimate authority over aircraft in flight belongs to pilots – but they have to follow air traffic control instructions and the rules of the air.

The air route network

As they fly the aircraft through the sky, pilots follow pre-planned routes, much like highways on the ground.

In the past, these routes followed national boundaries, but this is clearly not the most efficient way to criss-cross Europe. A more rational route network is constantly being developed so that flights can proceed more quickly and use less fuel.

Using less fuel is good for the environment, and for the airlines’ bottom-line.

Optimising Europe’s airspace

In 1992, the International Civil Aviation Organisation ’s  European Air Navigation Planning Group (ICAO EANPG) invited EUROCONTROL “to organise and carry out the necessary coordination of planning and implementation activities for improving and upgrading the ATS (Air Traffic Services) route network in the European Civil Aviation Conference (ECAC) area (44 States)”.

Today, our Airspace Design activity helps air navigation service providers (ANSPs) to develop, coordinate, validate and implement proposals to optimise Europe’s airspace structure, for both en route and terminal airspace.

Airspace design, planning and implementation is consolidated through a coordination process called Cooperative Decision-Making, carried out on a Europe-wide basis as well as on regional, national and local levels.

The Route Network Development Sub-Group (RNDSG) of the Network Operations team prepares the groundwork. They begin with broad operational requirements that are gradually refined into specific airspace proposals for implementation:

Step 1 Current and potential problem areas - and their causes - are identified.
Step 2 If problems have been caused by inefficiencies in the airspace structure, then airspace structure improvement proposals are developed to alleviate the problem, accommodate demand and balance ATC workloads
Step 3 Detailed proposals, together with their “modus operandi”, are elaborated, coordinated, refined and validated at local, regional and Network level. Proposals are assessed for their impact on both capacity and the environment (flight efficiency).
Step 4 A phased implementation programme is agreed upon and carried out.

Airspace design

The objective of Airspace Design is to create an efficient, flexible and dynamic airspace structure, based on multi-option routeings and areas of Free Route airspace operations. It needs to be supported by adaptable ATC sectorisation, one that will accommodate future air traffic demand and meet the Single European Sky Performance Scheme’s requirements in terms of capacity and flight efficiency, in a cost-effective manner.

The design of the European Route Network, as described in Annex 1 of EC Regulation No 677/2011 (the Network Management Implementing Rule – or the NM IR) calls for the establishment of a European Route Network Improvement Plan.

The Network Manager has to develop - through a cooperative decision-making process - the European Route Network Improvement Plan as part of the Network Operations Plan. This strategic plan has to be approved each year by the Network Manager’s governance structure.

According to the NM IR, the European Route Network Improvement Plan must contain:

  • common general principles complemented by technical specifications for airspace design;
  • military airspace requirements;
  • an agreed European route network and, where feasible, a free route airspace structure designed to meet all users’ requirements with details covering all the airspace change projects;
  • route network and free route airspace utilisation rules and availability;
  • indications on recommended ATC sectorisation and sector families;
  • guidelines for airspace management;
  • a defined development timetable;
  • a calendar for a common publication and implementation cycle, through the Network Operations Plan;
  • an overview of the current and expected Network situation, based on current and agreed plans.

Airspace modelling

Before agreeing on changes and improvements, simulations of how the new airspace would work in practice have to be carried out.

We have a variety of sophisticated modelling and simulation tools to refine and validate airspace design proposals. We carry out operational analysis of airspace structure (route network and sectorisation) combined with various traffic distribution options. The tool-set is complemented by a comprehensive database of past, present and future airspace and demand data, the Demand Data Repository.

The tools and data are given to air navigation service providers for their local planning purposes; they also have access to training and a support package. Our Airspace Design team helps ANSPs develop major airspace design projects, providing operational and technical expertise.

The objectives of airspace modelling are:

  • to conduct a quantitative analysis of potential European airspace changes;
  • to validate airspace concepts;
  • to assess their impact on capacity and flight efficiency using mathematical simulation models.

The scope of the modelling ranges from changes to individual Air Traffic Services (ATS) units to those which encompass the entire European airspace and ATS route network.

In this dossier

The Operations Performance Planning activity provides a...