What is the status of TCAS II version 7.1 implementation?
The TCAS II MOPS were revised following the identification by EUROCONTROL of two safety issues in the existing TCAS logic (one relating to the performance of the RA-reversal logic, and the other involving incorrect responses to Adjust Vertical Speed RAs). The FAA is expected to publish the TCAS II version 7.1 Technical Standard Order (TSO) in early 2009; the EASA TSO will follow later in the year. Studies indicate that currently the probability of a mid-air collision in European airspace is one in every 3 years. When version 7.1 is implemented that probability will reduce by a factor of 4. EUROCONTROL believes that prompt action by Regulators is required to mandate forward and retrofit of TCAS II version 7.1 in European airspace as rapidly as possible. However, the implementation schedule has not yet been established.
