Purpose: This document sets forth the characteristics of a Terrain Awareness and Warning System (TAWS) intended for installation in aircraft with digital signal interfaces. The intent of this document is to provide general and specific guidance for the development and installation of the TAWS unit primarily for airline use. This Characteristic describes the desired operational capability of the equipment, the standards necessary to ensure interchangeability, form factor, and pin assignments.

Equipment manufacturers should note that this document aims to encourage them to produce maintenance-free, high performance equipment rather than that of minimum weight and dimensions. They are at liberty to accomplish this objective by means of design techniques they consider to be the most appropriate, as their airline customers are interested primarily in the end result rather than the means employed to achieve it.

This Characteristic is constructed using ARINC 723 as the basis for the GPWS modes 1 through 6 design, descriptions, and functionality. This Characteristic describes two types of TAWS installations. This includes (type 1) first generation TAWS equipment with wiring limitations resulting from GPWS aircraft installations and (type 2) future generation equipment.

ARINC 762 type 1 units use manufacturer-specific program pins for configuration.

ARINC 762 type 2 units include a TAWS Configuration Module (TCM), expanded ARINC 429 interfaces and 10 BaseT Ethernet interfaces.

COMMENTARY: There has been discussion of ARINC 762 type 3 units that would use 100 BaseTX Ethernet capability with advanced display systems.