Description / Abstract: Since the introduction of TCAS II, opposite reactions to Negative Resolution Advisories (RAs) have been regularly identified and have continued with TCAS II Version 7. Special Committee 147 was tasked to analyze the display configurations and aural alerts for Negative RAs. The purpose of this work was to determine whether problems exist with current display and annunciation requirements for this class of RA. This report documents results of SC-147's analysis and recommends an approach for resolving identified problems.

The report is structured as follows:

• Section 1 provides an introduction into the issues being investigated and a high level overview of the work.
• Section 2 describes the implementation of various types of RA displays
• Section 3 describes the data used in developing the conclusions and recommendations.
• Section 4 presents the conclusions reached.
• Section 5 presents recommendations for corrective actions to reduce the frequency of opposite responses to Negative RAs. The section also presents recommendations for further work on other related issues.
• Appendices are also included in the report to provide additional details on related issues, data collection methodology, and data results.