EXECUTIVE SUMMARY:
The goal of this document is to investigate the capabilities of current and futures data-link technologies (in association with the ground segment define in the Work Package 2.2.7), to select the best fitted technologies and to define the weather air-ground data-link service to meet the FLYSAFE objectives.
This document provides the following parts:

• An overview of the aeronautical application classification, current data link technologies for all aeronautical functions, aeronautical networks and the data link service providers, the future data link technologies envisaged for medium and long terms and an overview of institutional data link studies’ results.
• A list of data link technologies is determined for short term solutions (platform / 2008) and longer term solutions (target / 2020).  A list of weather data link criteria is defined followed by a developed evaluation process to assess the capability of each technology to meet the FLYSAFE weather products requirements. The evaluation process has only been developed for the short term data link solution. We have not enough information for long term data link solution and most future data link technologies are under development. At the end, a set of recommendations is given to make to select the best data-link technologies according to the FLYSAFE use.
• According to information from D 2.2.1 document, a list of ground weather products is defined with characteristics from the data link point of view.
• At the end, this document defines the weather data-link service to be envisaged as a future data-link application. This service is describe with a global view of the weather data-link system with the definition of the several entities of the system, the weather corridor concept, the type of message exchanged between the ground and the aviation user and the delivery methods.