A United Airlines flight from London to Houston experienced a loss of vertical separation with a FedEx aircraft flying in the opposite direction.
Two Boeing 777-200 aircraft lost vertical separation over the Atlantic during opposite-direction flights in Canadian-controlled airspace.
Saturday, June 21 2025, the United Airlines flight UA879 was flying from London Heathrow to Houston while FedEx flight FL10 departed from Memphis to Paris Charles de Gaulle Airport.
According to the Canadian TSB report, the incident occurred when “the controller issued a CPDLC clearance direct to TOPPS, which inadvertently included a level change to FL360.” Recognizing the error immediately, the controller issued voice instructions to the United crew to maintain 34,000 feet.
Pilots of the United Boeing 777 (registration N78002) reported a TCAS advisory and descended back to FL340 after reaching FL345.
The TSB reported separation of 1000 feet vertical with the FedEx Boeing 777 (registration N879FD) was re-established within seconds and both flights continued to their destinations says The Aviation Herald.
