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Outline Safety Case: Enhanced Real Time Civil-Military Co-ordination (OI-1B)

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This document contains the Outline Safety Case for the Enhanced Flexible Use of Airspace Process Operational Improvement 1B (OI-1B) which concerns enhanced real time civil/military co-ordination. It presents the argument why e-FUA OI-1B is acceptably safe in principle to implement in European Civil Aviation Conference (ECAC) States together with supporting evidence.

All European Civil Aviation Conference (ECAC) States should verify that the assumptions, safety assessment scope and conclusions of this Outline Safety Case are applicable to their specific national circumstances prior to implementing OI-1B in their State. Alternatively States may determine that changes are acceptably safe through their own documented safety assessment work.

EUROCONTROL has shown, as far as it is able, against clearly defined generic assumptions and definitions that e-FUA OI-1B is acceptably safe in principle for implementation in European Civil Aviation Conference (ECAC) States. This assurance is documented in this Outline Safety Case.

Each individual European Civil Aviation Conference (ECAC) State intending to implement e-FUA OI-1B is responsible for:

  • Reviewing the Outline Safety Case for e-FUA OI-1B produced by EUROCONTROL; and
  • Either determining that the Outline Safety Case is wholly transferable to circumstances in their own State, or identifying additional safety assessment activities that need to be performed to make the Outline Safety Case transferable to their own State and executing these tasks satisfactorily. In both cases the process followed and the results obtained by the implementing States must be documented in their National Safety Case.

Alternatively, a State may perform their own safety assessment of e-FUA OI-1B independent of the EUROCONTROL Outline Safety Case.


The Flexible Use of Airspace (FUA) Concept is intended to provide the maximum flexibility to all airspace users in a seamless fashion across all ECAC States.

The basis of the FUA Concept is that airspace should no longer be designated as either military or civil airspace but instead should be considered as one continuum and used flexibly by all airspace users on a day-to-day basis. Thus any required segregation of Operational Air Traffic (OAT – mostly military aircraft) and General Air Traffic (GAT) should be achieved by the temporary allocation of airspace.

The general airspace management (ASM) functions and procedures needed to fully exploit the FUA Concept are specified in the EUROCONTROL Handbook for Airspace Management. The planning elements and methods of application for a common airspace design and change process in the ECAC Region are contained in the EUROCONTROL Manual for Airspace Planning.

Basic FUA (b-FUA) was introduced in early 1996. A list of minimum requirements has been established to define the main criteria and the essential organisational structures and procedures that shall be completed by the State in order to comply with the b-FUA implementation. By the end of 1998 b-FUA was implemented in 13 ECAC States and is currently implemented in almost all ECAC States. b-FUA is a prerequisite for all OIs under Enhanced FUA (e-FUA), including OI-1B.

EUROCONTROL’s Airspace Strategy document identifies a coherent set of actions, grouped into seven Directions for Change (DfC), with the objective of contributing to a single European Sky sometime after 2015. Within the Airspace Strategy DfC B is titled “Airspace Management & Civil/Military Co-ordination”.

Within DfC B, the following 6 Operational Improvements (OI-1B to OI-6B) have been identified along with the stated target implementation timeframe:

  • OI-1B Enhance real-time civil/ military co-ordination.
  • OI-2B National collaborative/ integrated airspace planning, to be complete by Q3 2004.
  • OI-3B Extend FUA to lower airspace, to be complete by Q4 2005.
  • OI-4B Enhance FUA with dynamic airspace allocation and harmonise OAT/ GAT handling throughout Europe, to be complete by Q4 2006.
  • OI-5B Collaborative European airspace planning, to be complete by 2008.
  • OI-6B Integrated European airspace, to be complete by 2012.

These Operational Improvements are collectively called the Enhanced FUA Process.

Within FUA, airspace use is planned with reference to 3 organisational levels:

  • Level 1 concerns strategic planning months or years in advance of use;
  • Level 2 concerns pre-tactical planning up to 1 day in advance of use; and
  • Level 3 concerns tactical planning and co-ordination on the day of operations.

This Outline Safety Case (OSC) concerns enhanced real time civil military co-ordination (OI-1B) which relates exclusively to Level 3.

The main objective of the Operational Improvements under e-FUA is to increase airspace capacity whilst maintaining, or improving where practicable, the safety levels accepted under b-FUA. Operational Improvement 1B under Enhanced FUA consists of 3 main changes as follows:

  • Change 1 – The passive exchange of flight data (basic flight plan data and current flight plan data) from the military controller to the civil controller.
  • Change 2 – The silent exchange of flight data between civil and military controllers to support the airspace crossing function.
  • Change 3 – The provision of airspace structure status information via the Airspace Data Repository.

It should be noted that OI-1B does not change the civil-military co-ordination process. It only changes the means by which that co-ordination process is accomplished.

Top Level Claim

Enhanced-Future Use of Airspace Operational Improvement-1B (e-FUA OI-1B) is acceptably safe in principle for implementation in ECAC States.

General Assumptions

This Outline Safety Case for e-FUA OI-1B concerns ATM issues that arise from OAT and GAT interactions in controlled airspace above FL 195 that are supervised by civil-military coordination procedures at the tactical level (Level 3), consistent with the definition of OI-1B. It is assumed that this involves Class C airspace, with negligible amount of VFR, and that only within state co-ordination is considered. This generic assumption has been expanded into a number of more detailed assumptions divided into three areas.

Assumptions Related to Scope of Safety Assessment

  1. OI-1B will be applied only to controlled airspace above FL 195.
  2. OI-1B will be applied only to Class C airspace above FL 195 where Visual Flight Rules (VFR) GAT activity is negligible.
  3. OI-1B will be applied only to within State co-ordination

Assumptions Related to Operation of b-FUA and OI-1B.

  1. Civil and military controllers are separate entities and are not co-located. This assumption is a worst case because some European Civil Aviation Conference (ECAC) States already co-locate their controllers, or provide integrated ATC. Co-location or full integration is expected to result in safety benefits, though these have not been evaluated.
  2. CNS/ ATM capabilities:
    • Primary radar assumed to detect both OAT and GAT.
    • Secondary radar surveillance of OAT by military-controller and GAT by civil-ATC assumed respectively.
    • GAT detected directly by military secondary radar.
    • OAT detected directly by civil secondary radar.
    • VHF voice communication assumed between civil-ATC and GAT and between military-ATC and OAT.
  3. Silent mode requires additional electronic data entry from both civil and military controllers. Passive mode requires additional electronic data entry from the military controller.
  4. Civil controllers are responsible for separation between GAT. Military controllers are responsible for separation of OAT-GAT and OAT-OAT.

Assumptions Related to the Safety Argument for OI-1B

  1. Basic-FUA (b-FUA) is acceptably safe.
  2. Human error rates for electronic communication (passive and silent modes) are similar to or less than verbal communication error rates. The assumption here is that this is generally true, whereas there is only limited and/or generic quantitative data.
  3. It has been assumed that the Airspace Data Repository (Change 3) of OI-1B is safer than b-FUA (multiple bi-lateral communication of airspace status).
  4. Safety assessment of OI-1B is assumed to be possible independent of other OIs under DfC B.
  5. If e-FUA operations revert to b-FUA (verbal telephone communication) for any reason it is assumed that the risks are identical to current b-FUA risks. The implementation of OI-1B must not degrade the performance of b-FUA coordination methods.
  6. Controller workloads after implementation of OI-1B are assumed to be similar to those under b-FUA.

Associated Hazards

Related Regulations and Standards

  1. EUROCONTROL Handbook for Airspace Management, edition 2.0, 23/10/2007, or a more recent version;
  2. EUROCONTROL Manual for Airspace Planning, Common Guidelines, edition 2.0; 22/10/03
  3. EUROCONTROL, 2003: “Guidance Document for the Implementation of the Concept of the Flexible Use of Airspace”, ASM.ET1.ST08.5000-GUI-02-00, Edition 2.0, 18/08/03
  4. EUROCONTROL , 2001: “EUROCONTROL Airspace Strategy for ECAC States”, ASM.ET1.ST03.4000-EAS-01-00, Edition 1.0, 18/01/01
  5. EUROCONTROL, 1994: “Report on Organisational Structures and Procedures Required for the Application of the Concept of the Flexible Use of Airspace”, Doc.94.70.08, March 1994
  6. EUROCONTROL, 1996: “Functional Specifications for System Support to Airspace Data Distribution and Civil/Military Co-ordination”, DPS.ET1.ST10.2000-FS-01-00, Edition 1.0, 15/05/96
  7. EUROCONTROL, 2001: "Risk Assessment and Mitigation in ATM", EUROCONTROL Safety Regulatory Requirement (ESARR) 4, Edition 1.0

Document Source

Further Reading

  • EUROCONTROL Safety Case Development Manual, edition 2.2, 13 November 2006,
  • EUROCONTROL, 2004: “Enhanced FUA Process Safety Policy”, Proposed Issue, Edition 1.0, 22/03/04
  • EUROCONTROL, 2004: “Enhanced FUA Process Safety Plan”, Proposed Issue, Edition 1.0, 22/03/04</protect>