EUROCAE and RTCA have jointly developed revised Minimum Operational Performance Standards (MOPS) for Traffic alert and Collision Avoidance System (TCAS) II published in [ED-143] and [DO-185B] respectively, to be known as TCAS II version 7.1 Fifteen scenarios for the introduction of TCAS II version 7.1 have been investigated in the study involving a range of start and completion dates for the transition phase and various speeds of retrofits, including the “late rush retrofit hypothesis.