Mandates: TCAS Change 7.1

There’s no question that Traffic Alert and Collision Avoidance Systems (TCAS) and Airborne Collision Avoidance Systems (ACAS) have had a significant beneficial impact on aviation safety since initial government-mandated implementations began in the mid-1990s.

TCAS is designed to reduce mid-air collisions between aircraft by monitoring the airspace around an aircraft for other aircraft equipped with compliant transponders, independent of air traffic control. The system can proactively warn pilots of the presence of the other transponder-equipped aircraft that may present a collision threat.

With Change 7.1, the European Aviation Safety Agency (EASA) estimates that mid-air collision risk decreases by factor of four.

Two primary safety-related issues are addressed in Change 7.1:

  • Based on a series of incidents between 2001 and 2002, including one collision, in France, Belgium, Japan and Germany, one change proposal (CP 112E) corrects an issue with TCAS-TCAS reversals. In prior versions, if an equipped aircraft was instructed by TCAS to descend and the “intruder” aircraft either was not equipped or was instructed by Air Traffic Control to descend, a collision could occur. The new version allows TCAS to reverse its instruction far sooner when it senses non-compliance from the other aircraft.
  • The other proposal (CP 115) changes the current TCAS II aural warning “Adjust Vertical Speed, Adjust” to “Level Off, Level Off.”

To talk to a Honeywell expert, fill out the form below:


Get in Touch


Let us know how our sales team can help.

Contact Sales


Looking for support on a product or service you already use?

Contact Support


Find an authorized Dealer, Distributor, or Service Center.

Search Directory

Contact Sales

Thank you for filling in the form!

Contact Support

To contact support, visit Please note, for the best experience, you may be asked to log in.

Search Directory

Inclusion in this directory does not imply a channel partner is authorized to maintain, repair or overhaul all Honeywell products. Contact Sales with questions.