October 6, 2011 - RTCA

Agenda Item 4.b ASIAS/CAST/CAS Steering Committee
There were no discussions under this agenda item.
Agenda Item 5. Working Group Status Reports
Agenda Item 5.a Requirements Working Group (RWG)
Andy Zeitlin provided a summary of the RWG’s work since the last Plenary meeting. The main
focus is preparing a report on future collision avoidance systems and work on that report has been
completed. Andy’s report provided an overview of the contents and recommendations from the
report. The report identifies both near-term and long-term improvements that could be
incorporated into the collision avoidance logic.
The contents of the report were reviewed this week by the RWG and the RWG is in agreement
with the current version of the report. Following the completion of a few editorial cleanup
changes, the report will be ready for distribution to the Committee for review and comment.
To support the delivery of the report to the Program Management Committee (PMC) in
December 2011, the following distribution and review schedule was agreed to during the
meeting.
Initial Distribution October 19, 2011
Comments Due Back to Andy November 7, 2011
Telecon/Webex to Review Comments November 9, 2011
Deliver to PMC November 30, 2011
Agenda Item 5.b Surveillance Working Group (SWG)
Ruy Brandao provided a status report on the SWG’s work. Since the last SC-147 meeting, work
has continued to develop and evaluate means of reducing the TCAS utilization of the 1090 MHz
frequency. A simulation model that was previously developed was updated to incorporate all six
specific change proposals and testing was done with all of the various proposals. Simulations
show that Changes to DO-300 would result in 1090 MHz utilization reduction of 60% to 85%
when all simulated TCAS II equipped aircraft have these changes implemented. Additional
change proposals have been defined which would further reduce the contributions of on-ground
TCAS to 1090 MHz utilization. Evaluation of the benefits of these changes is expected to be
complete by the end of the year. Safety studies do not show any degradation in risk ratio when
these changes are implemented.
The SWG recommended that the Terms of Reference be amended to allow incorporation of these
changes in the MOPS. The SWG will continue work on the change proposals under the
assumption that the Terms of Reference will be updated. This may result in changes to DO-
185B, DO-300, or both.
The SWG also proposed allowing TAs to be issued based solely on ADS B data (for hybrid
surveillance equipped aircraft) if the intruder was not already being interrogated and then
switching to active interrogations immediately after the TA was issued. The Committee agreed
with this proposal.
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