A Formally Verified Hybrid System for the Next-Generation Airborne Collision Avoidance System

  • Jean-Baptiste Jeannin
  • Khalil Ghorbal
  • Yanni Kouskoulas
  • Ryan Gardner
  • Aurora Schmidt
  • Erik Zawadzki
  • André Platzer
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9035)


The Next-Generation Airborne Collision Avoidance System (ACAS X) is intended to be installed on all large aircraft to give advice to pilots and prevent mid-air collisions with other aircraft. It is currently being developed by the Federal Aviation Administration (FAA). In this paper we determine the geometric configurations under which the advice given by ACAS X is safe under a precise set of assumptions and formally verify these configurations using hybrid systems theorem proving techniques. We conduct an initial examination of the current version of the real ACAS X system and discuss some cases where our safety theorem conflicts with the actual advisory given by that version, demonstrating how formal, hybrid approaches are helping ensure the safety of ACAS X. Our approach is general and could also be used to identify unsafe advice issued by other collision avoidance systems or confirm their safety.


Hybrid System Markov Decision Process Safe Region Implicit Formulation Federal Aviation Administration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Jean-Baptiste Jeannin
    • 1
  • Khalil Ghorbal
    • 1
  • Yanni Kouskoulas
    • 2
  • Ryan Gardner
    • 2
  • Aurora Schmidt
    • 2
  • Erik Zawadzki
    • 1
  • André Platzer
    • 1
  1. 1.Carnegie Mellon UniversityPittsburghUSA
  2. 2.The Johns Hopkins University Applied Physics LaboratoryLaurelUSA

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