On December 16, 2011, the European Commission published Implementing Rule 1332/2011 mandating the carriage of ACAS II version 7.1 within European Union airspace from December 1, 2015 by all aircraft currently equipped with version 7.0 and from 1 March 2012 by all new aircraft above 5,700 kg maximum take-off mass or a maximum passenger seating capacity of more than 19.
Version 7.0 Safety Issues
Since its introduction in Europe in 2000, TCAS II version 7.0 has been the subject of monitoring. In the course of analyzing recorded and reported events, many cases were found in which pilots did not respond correctly to the “Adjust vertical speed, adjust” Resolution Advisories (RA) – the vertical rate was increased rather than reduced.
Additionally, there have also been a number of cases in which TCAS II version 7.0 failed to reverse an RA when two converging aircraft remained within 100 feet. This type scenario would be occur when one aircraft is not following the RA or is not TCAS II equipped and follows an ATC instruction or performs an avoidance maneuver based on visual acquisition.
Adjust Vertical Speed
“Adjust Vertical Speed, Adjust” (AVSA) RA was determined to be confusing, and there is a history of some pilots not responding as intended. The solution in Change 7.1 is to replace the four AVSA RAs with a single “Level Off, Level Off” RA.
TCAS reversals were introduced in 7.0 to adapt to changing situations where the original guidance became the wrong thing to do if one of the pilots did not follow the RA or was instructed by ATC to perform a particular maneuver. Change 7.1 improves this reversal logic to address late issuance of reversal RAs and potential failures to initiate reversal RAs.
Honeywell's TCAS Change 7.1 Solutions
Honeywell’s TPA-100B Traffic Computer Change 7.1-compliant design meets the challenge for its broad base of airline and business aviation customers with solutions that not only meet the mandate requirements but provide a number of benefits ranging from fuel savings, greater situational awareness, fewer delays and expensive AOG situations.
Jet Aviation, one of the leading business aviation services companies in the world, recently completed STCs on the Dassault Falcon 20, Learjet 31 and Germany-based Aero-Dienst completed certification for the Learjet 35/36.
For owners of the Bendix/King (Honeywell) CAS-67A processor, Pro Star Aviation has developed an STC to address the EASA mandate. In December 2014, The FAA issued an approved model list (AML) STC to Pro Star for upgrade of BendixKing CAS 67A Change 7.0 to CAS 67B Change 7.1 for operators of many popular business aircraft including various Beech, Boeing, Bombardier, Cessna, Dassault, Gulfstream, Learjet, Lockheed and Sabreliner models. STCs are in progress for the other affected platforms.
Operators and dealers can contact their Bendix/King sales representative for more information about STC ST00347BO and to get a list of approved models.
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