SCOPE AND OBJECTIVE

The objective of this OSED is to provide the background to define the Safety and Performance Requirements (SPR) and Interoperability (INTEROP) documents for data link service(s) incorporating AIS and/or MET information. As shown in Figure 2-1, the aim is to provide aeronautical information for:

• Pilot decision support; and

• Collaborative Decision Making (CDM) between ground services, the flight deck, Air Traffic Control (ATC) and, as appropriate, Airline Operations Centers (AOCs) in all flight environments for flight efficiency and/or hazard avoidance.

The data link service descriptions are media independent and cover both one-way (broadcast) and two-way (demand and/or contract) data link system architectures for transmitting AIS and/or MET information to and from the aircraft. Section 5 contains more detailed descriptions of the various data link modes to include the downlink transmissions of aircraft MET data to the ground or the crosslink transmissions to other aircraft in the vicinity.

The data link services that provide ground-based information to the aircraft are classified by either the type of AIS information provided, or for MET information, by the time available to support a pilot decision making process. The decision time factor is based on the time between when information is made available and when the aircraft will potentially encounter the operational constraints or opportunities to be addressed by the pilot decision.

The data link services defined in this document are AISLINK and METLINK services as listed below:

AISLINK services (described in terms of how the data is changed or updated):

• Aeronautical Update Service

• Baseline Synchronization Service and

METLINK services (described in terms of the immediacy of the decisions they support for WPDS, WNDS and WIDS listed below):

• Weather Planning Decision Service (WPDS)

• Weather Near-Term Decision Service (WNDS)

• Weather Immediate Decision Service (WIDS)

• Weather Downlink and Crosslink Service.

There are many common functions and attributes that will be included in the provision of data link service(s) for AIS and MET information. These common functions and attributes are described in Sections 3 through 5; and the details for the data link services are described in subsequent Section 6 for AISLINK and Section 7 for METLINK.

It is anticipated that operational deployments of AIS/MET data link system(s) may incorporate combinations of AIS and MET information derived from several, if not all of the AISLINK/METLINK services described in this OSED. Under such circumstances, the SPR and INTEROP requirements describing the capabilities of the data link would be driven by the most stringent requirements of the services offered over that link.