Swiss Boeing 777 declares emergency over Atlantic, diverts to Azores

A Swiss International Air Lines Boeing 777-300ER flying as flight LX9 from Chicago to Zurich diverted to the Azores after its crew transmitted a 7700 transponder code over the Atlantic Ocean.

The aircraft, registered HB-JNF, landed at around 08:30 Central European Time at Lajes Air Base on the island of Terceira, a military airfield that also handles civilian traffic. A Swiss spokesperson confirmed to a media outlet that the aircraft had diverted, but gave no further details on what prompted the emergency squawk.

A 7700 code tells air traffic control that a crew is dealing with a general emergency. That can mean engine trouble, smoke or fire onboard, a medical emergency, or loss of cabin pressure. The code does not necessarily mean the aircraft is in imminent danger; crews sometimes set it as a precaution while they assess a problem.

Once a 7700 code is set, controllers typically give the aircraft priority handling. They clear traffic from its path and, where needed, direct it to the nearest suitable airport. Emergency services are often put on standby as a precaution.

No further information on the nature of the malfunction, injuries, or passenger numbers has been released. Swiss has not yet said when the aircraft or its passengers will continue on to Zurich.