# Proposed AD FAA-2010-1204: Aviation Communication & Surveillance Systems (ACSS) Traffic Alert and Collision Avoidance System (TCAS) Units

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-02-08
- Products: Aviation Communication & Surveillance Systems
- Product type: Appliance
- Action: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
- Published: October 7, 2011, 76 FR 62321
- Comments due: November 7, 2011
- Became: [AD 2012-02-08](https://openairdocs.org/ad/2012-02-08)
- Docket: FAA-2010-1204 (https://www.regulations.gov/docket/FAA-2010-1204, where comments are filed)
- Project: 2010-NM-147-AD
- FR document: 2011-26084
- Official PDF: https://openairdocs.org/files/sha256/09/c7/09c73f4953d7ede04e6797cf7e095c08e7c4e0a2fc889272ae8e86e8d2bf1b81 (from https://www.govinfo.gov/content/pkg/FR-2011-10-07/pdf/2011-26084.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/10/07/2011-26084/airworthiness-directives-aviation-communication-and-surveillance-systems-acss-traffic-alert-and
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D39C946452F46B5E86257922004ABD8D.0001
- Page: https://openairdocs.org/proposed/FAA-2010-1204

## Summary

We are revising an earlier proposed airworthiness directive (AD) for certain Aviation Communication & Surveillance Systems (ACSS) traffic alert and collision avoidance system (TCAS) units installed on but not limited to various transport and small airplanes. That NPRM proposed to require upgrading software. That NPRM was prompted by reports of anomalies with TCAS units during a flight test over a high density airport. The TCAS units dropped several reduced surveillance aircraft tracks because of interference limiting. This action revises that NPRM by proposing to require new updated software for certain TCAS units. We are proposing this supplemental NPRM to correct the unsafe condition on these products. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

## Notices in this docket

- Dec 28, 2010: Notice of proposed rulemaking (NPRM). (first notice), FR document 2010-32658, comments due Feb 11, 2011 (https://www.federalregister.gov/documents/2010/12/28/2010-32658/airworthiness-directives-various-aviation-communication-and-surveillance-systems-acss-traffic-alert)
- Oct 7, 2011: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document 2011-26084, comments due Nov 7, 2011 (https://www.federalregister.gov/documents/2011/10/07/2011-26084/airworthiness-directives-aviation-communication-and-surveillance-systems-acss-traffic-alert-and)

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