Airborne Collision Avoidance Systems (ACAS) Safety Studies

Airborne Collision Avoidance Systems (ACAS) Safety Studies

Since the introduction of the Airborne Collision Avoidance System (ACAS), a number of studies relating to its performance and safety have been commissioned by EUROCONTROL. On this page, we provide a list of the studies (in the chronological order), their brief description and links to documents and presentations with details findings and conclusions.

ACASA: Airborne Collision Avoidance Systems Analysis (2001-2002, updated 2009)

A series of studies, supporting the mandate and implementation of ACAS II in Europe (2002):

Emotion-7: European Maintenance of TCAS II Version 7.0 (2003)

European Maintenance of TCAS II Version 7.0 established a framework to minimise the risks associated with TCAS II Version 7 operations in Europe.

Summary of ACAS II Safety Studies prior to 2004 (2004)

A paper summarizing ACAS II safety studies conducted prior to 2004.

SIR Projects: Safety Issue Rectification Projects (2004-09)

Safety Issue rectification - a series of studies (SIR, SIRE, SIRE+) commissioned by EUROCONTROL in order to improve ACAS safety performance.

IAPA: Implications on ACAS Performances due to ASAS implementation (2005)

The interaction between ACAS II and the operational use of the future Airborne Separation Assurance Systems (ASAS) has been thoroughly investigated within the scope of the IAPA project. The IAPA project analyses potential operational and safety implications, and provides guidelines for the development of future ASAS applications in Europe.

ASARP: ACAS Safety Analysis post-RVSM Project (2006)

ASARP measured and analysed the actual safety performance of ACAS II in European Reduced Vertical Separation Minima (RVSM) airspace.

Safety Benefit of ACAS II on Helicopters (2006-2008)

EUROCONTROL conducted a study to assess the feasibility and potential safety benefits of fitting ACAS II to helicopters. In parallel, a UK helicopter operator performed trial installation and operational evaluation on one of its helicopters.

FARADS: Feasibility of ACAS RA Downlink Study (2007)

Feasibility study to determine operational and safety benefits of providing ACAS RA Downlink and display to controllers.

I-AM-SAFE: IAPA – ASARP Methodology for Safety nets Assessment – Feasibility Evaluation (2007)

In the context of Short Term Conflict Alert (STCA) standardisation undertaken in Europe at the time, the I-AM-SAFE project evaluated the applicability and usefulness of the methodology used in the ACAS field in the prospect of establishing quantified performance requirements for STCA.

AVAL: ACAS on VLJs and LJs (2007-2009)

AVAL project (ACAS on Very Light Jet (VLJ) / Entry Level Jet (ELJ) Operations and LJs – Assessment of safety Level) investigated the potential effect of Very Light Jets (VLJ) and other Light Jets (LJ) on the safety benefit delivered by ACAS II.

PASS Project: Performance and Safety Aspects of Short-term Conflict Alert (2007-2010)

The objective of PASS is to examine the performance of the ground-based Short Term Conflict Alert (STCA) and interactions between operational use of STCA and ACAS.

Investigation and analysis of TCAS II safety issues in the European airspace (2009)

The present study has reviewed the computations made previously with the most recent (2009) UK and French radar data. Additionally, the correctness of pilot responses to TCAS RA was examined.

CAUSE: Collision Avoidance Requirements for Unmanned Aircraft Systems (2010)

Study of Collision Avoidance Requirements for Unmanned Aircraft Systems was started in April 2009. The evolution of aerospace technologies in the field of unmanned aircraft systems (UAS), including autonomous operations, will impact European ATM as regards new military and civil applications. The CAUSE study will assess various aspects of potential UAS equipage with a collision avoidance system in addition to the sense and avoid functionality.

APOSC: ACAS II Post-Implementation Safety Case (2011)

Safety Case for ACAS II operations in European Civil Aviation Conference (ECAC) airspace following completion of the transition period for implementing Phase 2 of the European ACAS II Mandate.

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