FAA Warns of CPDLC Confusion in North Atlantic Airspace

The FAA is warning operators that incorrect or delayed handling of controller-pilot datalink communications (CPDLC) route uplinks in North Atlantic airspace is contributing to pilot errors and increased air traffic control workload.

In an Information for Operators, the FAA said flight crews’ failure to promptly and correctly load CPDLC route uplinks has led to what Gander Area Control Centre described as “significant flight crew confusion,” along with a “significant increase in frequency congestion, pilot errors, and ATC workload.”

The issue follows new North Atlantic procedures that discontinued blanket issuances of oceanic clearances and increased the use of route-specific clearances when a flight is not “cleared as filed.” Under updated guidance, any required changes to a flight plan must be addressed through specific ATC clearances. Gander ACC implemented the revised procedures in December 2024, introducing CPDLC route uplinks when flights were not cleared as filed.

According to the InFO, controllers observed that flight crews often responded “WILCO” to route uplinks but then replied to a follow-up “CONFIRM ASSIGNED ROUTE” message before loading the full new route. The FAA said this practice triggers out-of-conformance alerts and can distract controllers from higher-priority tasks.

The InFO also highlighted frequent misinterpretation of uplink messages UM79 and UM80. The guidance states that UM79, “CLEARED TO [point] VIA ROUTE CLEARANCE,” is “not a clearance to proceed direct” to that point, and that UM80, “CLEARED ROUTE CLEARANCE,” “is not a ‘cleared as filed’ message.”