ARINC 735B PDF

Purpose of this Document

This document describes a Traffic Computer with Traffic Alert and Collision Avoidance System (TCAS) functionality that provides the necessary interface definitions and protocols to accommodate the requirements of RTCA DO-185: Minimum Operational Performance Standards for TCAS (latest version applies).

Additionally, this document describes interfaces and protocols necessary to accommodate Cockpit Display of Traffic Information (CDTI) based on reception of Automatic Dependent Surveillance – Broadcast (ADS-B) data and Traffic Information Services – Broadcast (TIS-B) data. The equipment becomes TCAS with ADS-B and TIS-B functions added, as defined by RTCA DO-260: Minimum Operational Performance Standards for 1090 MHz (latest version applies)

COMMENTARY

The control and Human Machine Interface (HMI) for CDTI and ADS-B In have not been standardized. Therefore this specification attempts to provide interfaces which could potentially support many different options for control and interfacing. It is expected that actual aircraft installations will use a subset of these.

Older TCAS equipment (ARINC 735 and ARINC 735A compliant) is designed to be backward compatible with Mode S transponders defined by ARINC Characteristic 718, which are only compatible with RTCA DO-185. ARINC 735A equipment is compatible with Mode S transponders defined by ARINC 718 and 718A, which are compatible with both RTCA DO-185 and RTCA DO-185A.

ARINC 735B TCAS equipment (defined by this standard) is intended to be compatible with ARINC 718A transponders that provide extended squitter capability. ARINC 718 transponders may also be used. However, this will result in the loss of ADS-B transmit capability.

As of the release of this document, RTCA DO-185B requirements were not yet completed, but the essential interface level changes were considered captured. Therefore, we do not anticipate that changes planned for RTCA DO-185B will impact this document. The additional labels found in Attachment 19K and 19L are meant to capture the latest requirements. These labels include hybrid surveillance capability indications, RTCA DO- 185B compatibility, and TCAS-to-transponder part number reporting. Any changes to RTCA DO-185B that affect this document will be reflected in a future Supplement to this document.

RTCA MOPS for ASSAP/CDTI are under development at the time of this writing.