Story ID: 
ACSS Intros TCAS Change 7.1 Update
By: Chad Trautvetter
Caption: Aviation Communications & Surveillance Systems (ACSS) is readying a software update for the Phoenix company’s TCAS II and TCAS 2000 traffic alert and c
Word Count: 124
Aviation Communications & Surveillance Systems (ACSS) is readying a software update for the Phoenix company’s TCAS II and TCAS 2000 traffic alert and collision avoidance systems to fix two potentially serious problems in the way the technology warns pilots of traffic threats. The Change 7.1 software, due out in the fourth quarter, will add so-called “reversal logic” to the TCAS, as well as a new aural alert in place of “adjust vertical speed” resolution advisories (RA). Reversal logic would allow the TCAS to amend an RA if it sees the other aircraft taking the same corrective action–for example, both aircraft climbing to avert an imminent collision. The software corrects the second problem by replacing the “adjust vertical speed” command with a “level off” RA