Description / Abstract: This update aligns the scope of interoperability requirements for the FANS 1/A technology with the Continental SPR Standard (DO-290) to include interoperability for interface with HF Data Link (HFDL). The document, initially issued in September 2000, defines interoperability requirements for communication services and Air Traffic Services (ATS) applications and allocates these requirements to stakeholders. It covers: the ATS Facilities Notification (ATN) application, the Automatic Dependent Surveillance (ADS) application, the Controller Pilot Data Link Communication (CPDLC) application and the ARINC data communication.