As most operators using CPDLC in the U.S. are now familiar with, the initial implementation of U.S. Domestic En Route CPDLC demonstrated that certain avionics versions and configurations had a lower than expected transmission success rate. These were primarily on Business and General Aviation aircraft. As a result, the FAA decided to temporarily exclude these aircraft types from participating in U.S. Domestic En Route CPDLC services until necessary validations and corrective actions are accomplished.
The FAA is working with L3Harris Technologies, Communications Service Providers (CSP) and the Original Equipment Manufacturers (OEMs) to identify and resolve these avionics compatibility issues that are preventing the systems from attaining the desired performance. Business and General Aviation aircraft with avionics platforms shown to meet operational acceptability can participate in the CPDLC En Route trial.
Can I participate in the trial?
Only the Business and General Aviation aircraft types with avionics configurations shown in figure 1, are eligible to participate in the CPDLC En Route trials. Operators with aircraft on this list that desire to participate must sign up first. The current US Domestic En Route CPDLC Avionics Trial guide published on the L3Harris Data Comm site contains the table in figure 1 and instructions on how to fill out and submit the registration form.
Operators that plan to participate in the En Route trials must ensure that block 18 of the filed flight plan contains the proper codes showing En Route capability. Aircraft without route loading issues must file the DAT code (FANSE) to support a full UM80 loadable route when applicable. Aircraft that have known issues loading a route clearance with a STAR must file the DAT code (FANSER); for these aircraft, the assigned STAR will be appended as free text in the uplink message.
What if I am not eligible for the En Route trial?
Operators of aircraft types not listed or registered for the trial, must file as NOT eligible for En Route CPDLC by removing the block 18 DAT codes (FANSE or FANSER). The FAA has reported operators not registered for the trial are still attempting to log on to KUSA while airborne, or that the aircraft is filed as En Route CPDLC eligible. The FAA has recently re-emphasized the FDC NOTAM shown in figure 2.
Also, a last reminder: CPDLC DCL operations are independent of, and not impacted by the En Route trials and operators are encouraged to take advantage of it wherever it is available.