ASD-STAN/D 1/S 2 - MOAA Modular and Open Avionics Architecture

The purpose of this MOAA standard is to define a set of open architecture standards,
concepts & guidelines for Advanced Avionics Architectures (A3).
The three main goals for the MOAA Standards are:
— Reduced life cycle costs,
— Improved mission performance,
— Improved operational performance.
The MOAA standards are organised as a set of documents including:
— A set of agreed standards that describe, using a top down approach, the Architecture overview to all
interfaces required to implement the core within avionics system,
— The guidelines for system implementation through application of the standards.
This standard details the functionality and principle interfaces of an EN 4660 compliant network to
ensure the interoperability of Common Functional Modules and design guidelines to assist in
implementation of such a network.
The purpose of this standard is to establish by means of well defined interfaces and functionality, a
network design that is technology transparent and that is open to a multi-vendor market. Therefore,
specific data communication network topology, protocols and technologies are not identified in this
document.
Although the physical organisation and implementation of the network shall remain the System
Designers choice, in accordance with the best use of the current technology, it is necessary to define
interfaces and parameter sets in order to achieve a logical definition of the network with a defined
functionality. This definition includes:
— The generic functionality applicable to all networks.
— The logical interfaces to the Operating System and Module Support Layers.
— Optionally the physical interfaces to the Common Functional Modules (CFM).
This document identifies the principle interfaces for the Network, in Clause 4, and where appropriate,
provides requirements on network parameters to be defined.

This European standard establishes uniform requirements for Packaging for the Common Functional
Modules (CFM) within an Integrated Modular Avionic (IMA) system. It comprises the module physical
properties and the Module Physical Interface (MPI) definitions together with guidelines for IMA rack
and the operational environment.
The characteristics addressed by the Packaging Standard are:
Interchangeability:
 For a given cooling method all modules conforming to the packaging standard will function
correctly when inserted into any rack slot conforming to the standard for the cooling method.
 All modules conforming to the Module Physical Interface (MPI) definitions for connector, IED and
cooling interface will function correctly when inserted into any rack slot conforming to the same
MPI definition.
Maintainability:
 All modules are easily removable at first line.
 No special tools required at first line.
 No manual adjustment is necessary when installing modules. No tool is required for installation or
removal of the modules.
 Mechanical keying is provided that prevents insertion of a module into a rack slot that may cause
an unsafe condition.
The Module Physical Interface definition, contained within this standard, does not include the
properties of the signalling used in the optical interface (e. g. wavelength). These are covered in
EN 4660-003.

This European Standard establishes uniform requirements for design and development of software
architecture for modular avionics systems.